Stellar classification (English Wikipedia)

Jeffery, C. S.; Werner, K.; Kilkenny, D.; Miszalski, B.; Monageng, I.; Snowdon, E. J. (2023). "Hot white dwarfs and pre-white dwarfs discovered with SALT". Monthly Notices of the Royal Astronomical Society. 519 (2): 2321–2330. arXiv:2301.03550. doi:10.1093/mnras/stac3531.
Weidner, Carsten; Vink, Jorick S. (December 2010). "The masses, and the mass discrepancy of O-type stars". Astronomy and Astrophysics. 524. A98. arXiv:1010.2204. Bibcode:2010A&A...524A..98W. doi:10.1051/0004-6361/201014491. S2CID 118836634.
Baraffe, I.; Chabrier, G.; Barman, T. S.; Allard, F.; Hauschildt, P. H. (May 2003). "Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 209458". Astronomy and Astrophysics. 402 (2): 701–712. arXiv:astro-ph/0302293. Bibcode:2003A&A...402..701B. doi:10.1051/0004-6361:20030252. S2CID 15838318.
Sota, A.; Maíz Apellániz, J.; Morrell, N. I.; Barbá, R. H.; Walborn, N. R.; et al. (March 2014). "The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars". The Astrophysical Journal Supplement Series. 211 (1). 10. arXiv:1312.6222. Bibcode:2014ApJS..211...10S. doi:10.1088/0067-0049/211/1/10. S2CID 118847528.
Caballero-Nieves, S. M.; Nelan, E. P.; Gies, D. R.; Wallace, D. J.; DeGioia-Eastwood, K.; et al. (February 2014). "A High Angular Resolution Survey of Massive Stars in Cygnus OB2: Results from the Hubble Space Telescope Fine Guidance Sensors". The Astronomical Journal. 147 (2). 40. arXiv:1311.5087. Bibcode:2014AJ....147...40C. doi:10.1088/0004-6256/147/2/40. S2CID 22036552.
Prinja, R. K.; Massa, D. L. (October 2010). "Signature of wide-spread clumping in B supergiant winds". Astronomy and Astrophysics. 521. L55. arXiv:1007.2744. Bibcode:2010A&A...521L..55P. doi:10.1051/0004-6361/201015252. S2CID 59151633.
Nazé, Y. (November 2009). "Hot stars observed by XMM-Newton. I. The catalog and the properties of OB stars". Astronomy and Astrophysics. 506 (2): 1055–1064. arXiv:0908.1461. Bibcode:2009A&A...506.1055N. doi:10.1051/0004-6361/200912659. S2CID 17317459.
Lyubimkov, Leonid S.; Lambert, David L.; Rostopchin, Sergey I.; Rachkovskaya, Tamara M.; Poklad, Dmitry B. (February 2010). "Accurate fundamental parameters for A-, F- and G-type Supergiants in the solar neighbourhood". Monthly Notices of the Royal Astronomical Society. 402 (2): 1369–1379. arXiv:0911.1335. Bibcode:2010MNRAS.402.1369L. doi:10.1111/j.1365-2966.2009.15979.x. S2CID 119096173.
Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Robinson, P. E. (October 2003). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I". The Astronomical Journal. 126 (4): 2048–2059. arXiv:astro-ph/0308182. Bibcode:2003AJ....126.2048G. doi:10.1086/378365. S2CID 119417105.
Cenarro, A. J.; Peletier, R. F.; Sanchez-Blazquez, P.; Selam, S. O.; Toloba, E.; Cardiel, N.; Falcon-Barroso, J.; Gorgas, J.; Jimenez-Vicente, J.; Vazdekis, A. (January 2007). "Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters". Monthly Notices of the Royal Astronomical Society. 374 (2): 664–690. arXiv:astro-ph/0611618. Bibcode:2007MNRAS.374..664C. doi:10.1111/j.1365-2966.2006.11196.x. S2CID 119428437.
Sion, Edward M.; Holberg, J. B.; Oswalt, Terry D.; McCook, George P.; Wasatonic, Richard (December 2009). "The White Dwarfs Within 20 Parsecs of the Sun: Kinematics and Statistics". The Astronomical Journal. 138 (6): 1681–1689. arXiv:0910.1288. Bibcode:2009AJ....138.1681S. doi:10.1088/0004-6256/138/6/1681. S2CID 119284418.
Arias, Julia I.; et al. (August 2016). "Spectral Classification and Properties of the OVz Stars in the Galactic O Star Spectroscopic Survey (GOSSS)". The Astronomical Journal. 152 (2): 31. arXiv:1604.03842. Bibcode:2016AJ....152...31A. doi:10.3847/0004-6256/152/2/31. S2CID 119259952.
Maíz Apellániz, J.; Walborn, Nolan R.; Morrell, N. I.; Niemela, V. S.; Nelan, E. P. (2007). "Pismis 24-1: The Stellar Upper Mass Limit Preserved". The Astrophysical Journal. 660 (2): 1480–1485. arXiv:astro-ph/0612012. Bibcode:2007ApJ...660.1480M. doi:10.1086/513098. S2CID 15936535.
Walborn, Nolan R.; Sota, Alfredo; Maíz Apellániz, Jesús; Alfaro, Emilio J.; Morrell, Nidia I.; Barbá, Rodolfo H.; Arias, Julia I.; Gamen, Roberto C. (2010). "Early Results from the Galactic O-Star Spectroscopic Survey: C III Emission Lines in of Spectra". The Astrophysical Journal Letters. 711 (2): L143. arXiv:1002.3293. Bibcode:2010ApJ...711L.143W. doi:10.1088/2041-8205/711/2/L143. S2CID 119122481.
Fariña, Cecilia; Bosch, Guillermo L.; Morrell, Nidia I.; Barbá, Rodolfo H.; Walborn, Nolan R. (2009). "Spectroscopic Study of the N159/N160 Complex in the Large Magellanic Cloud". The Astronomical Journal. 138 (2): 510–516. arXiv:0907.1033. Bibcode:2009AJ....138..510F. doi:10.1088/0004-6256/138/2/510. S2CID 18844754.
Rauw, G.; Manfroid, J.; Gosset, E.; Nazé, Y.; Sana, H.; De Becker, M.; Foellmi, C.; Moffat, A. F. J. (2007). "Early-type stars in the core of the young open cluster Westerlund 2". Astronomy and Astrophysics. 463 (3): 981–991. arXiv:astro-ph/0612622. Bibcode:2007A&A...463..981R. doi:10.1051/0004-6361:20066495. S2CID 17776145.
Crowther, Paul A. (2007). "Physical Properties of Wolf-Rayet Stars". Annual Review of Astronomy & Astrophysics. 45 (1): 177–219. arXiv:astro-ph/0610356. Bibcode:2007ARA&A..45..177C. doi:10.1146/annurev.astro.45.051806.110615. S2CID 1076292.
Norris, Jackson M.; Wright, Jason T.; Wade, Richard A.; Mahadevan, Suvrath; Gettel, Sara (December 2011). "Non-detection of the Putative Substellar Companion to HD 149382". The Astrophysical Journal. 743 (1). 88. arXiv:1110.1384. Bibcode:2011ApJ...743...88N. doi:10.1088/0004-637X/743/1/88. S2CID 118337277.
Miszalski, B.; Crowther, P. A.; De Marco, O.; Köppen, J.; Moffat, A. F. J.; Acker, A.; Hillwig, T. C. (2012). "IC 4663: The first unambiguous [WN] Wolf-Rayet central star of a planetary nebula". Monthly Notices of the Royal Astronomical Society. 423 (1): 934–947. arXiv:1203.3303. Bibcode:2012MNRAS.423..934M. doi:10.1111/j.1365-2966.2012.20929.x. S2CID 10264296.
Crowther, P. A.; Walborn, N. R. (2011). "Spectral classification of O2-3.5 If*/WN5-7 stars". Monthly Notices of the Royal Astronomical Society. 416 (2): 1311–1323. arXiv:1105.4757. Bibcode:2011MNRAS.416.1311C. doi:10.1111/j.1365-2966.2011.19129.x. S2CID 118455138.
Kirkpatrick, J. D. (2008). "Outstanding Issues in Our Understanding of L, T, and Y Dwarfs". 14th Cambridge Workshop on Cool Stars. 384: 85. arXiv:0704.1522. Bibcode:2008ASPC..384...85K.
Kirkpatrick, J. Davy; Barman, Travis S.; Burgasser, Adam J.; McGovern, Mark R.; McLean, Ian S.; Tinney, Christopher G.; Lowrance, Patrick J. (2006). "Discovery of a Very Young Field L Dwarf, 2MASS J01415823−4633574". The Astrophysical Journal. 639 (2): 1120–1128. arXiv:astro-ph/0511462. Bibcode:2006ApJ...639.1120K. doi:10.1086/499622. S2CID 13075577.
Kirkpatrick, J. Davy; Cushing, Michael C.; Gelino, Christopher R.; Beichman, Charles A.; Tinney, C. G.; Faherty, Jacqueline K.; Schneider, Adam; Mace, Gregory N. (2013). "Discovery of the Y1 Dwarf WISE J064723.23-623235.5". The Astrophysical Journal. 776 (2): 128. arXiv:1308.5372. Bibcode:2013ApJ...776..128K. doi:10.1088/0004-637X/776/2/128. S2CID 6230841.
Deacon, N. R.; Hambly, N. C. (2006). "Y-Spectral class for Ultra-Cool Dwarfs". Monthly Notices of the Royal Astronomical Society. 371: 1722–1730. arXiv:astro-ph/0607305. doi:10.1111/j.1365-2966.2006.10795.x. S2CID 14081778.
Zuckerman, B.; Song, I. (2009). "The minimum Jeans mass, brown dwarf companion IMF, and predictions for detection of Y-type dwarfs". Astronomy and Astrophysics. 493 (3): 1149–1154. arXiv:0811.0429. Bibcode:2009A&A...493.1149Z. doi:10.1051/0004-6361:200810038. S2CID 18147550.
Dupuy, T. J.; Kraus, A. L. (2013). "Distances, Luminosities, and Temperatures of the Coldest Known Substellar Objects". Science. 341 (6153): 1492–5. arXiv:1309.1422. Bibcode:2013Sci...341.1492D. doi:10.1126/science.1241917. PMID 24009359. S2CID 30379513.
Leggett, Sandy K.; Cushing, Michael C.; Saumon, Didier; Marley, Mark S.; Roellig, Thomas L.; Warren, Stephen J.; Burningham, Ben; Jones, Hugh R. A.; Kirkpatrick, J. Davy; Lodieu, Nicolas; Lucas, Philip W.; Mainzer, Amy K.; Martín, Eduardo L.; McCaughrean, Mark J.; Pinfield, David J.; Sloan, Gregory C.; Smart, Richard L.; Tamura, Motohide; Van Cleve, Jeffrey E. (2009). "The Physical Properties of Four ~600 K T Dwarfs". The Astrophysical Journal. 695 (2): 1517–1526. arXiv:0901.4093. Bibcode:2009ApJ...695.1517L. doi:10.1088/0004-637X/695/2/1517. S2CID 44050900.
Delorme, Philippe; Delfosse, Xavier; Albert, Loïc; Artigau, Étienne; Forveille, Thierry; Reylé, Céline; Allard, France; Homeier, Derek; Robin, Annie C.; Willott, Chris J.; Liu, Michael C.; Dupuy, Trent J. (2008). "CFBDS J005910.90-011401.3: Reaching the T-Y brown dwarf transition?". Astronomy and Astrophysics. 482 (3): 961–971. arXiv:0802.4387. Bibcode:2008A&A...482..961D. doi:10.1051/0004-6361:20079317. S2CID 847552.
Burningham, Ben; Pinfield, D. J.; Leggett, S. K.; Tamura, M.; Lucas, P. W.; Homeier, D.; Day-Jones, A.; Jones, H. R. A.; Clarke, J. R. A.; Ishii, M.; Kuzuhara, M.; Lodieu, N.; Zapatero-Osorio, María Rosa; Venemans, B. P.; Mortlock, D. J.; Barrado y Navascués, D.; Martin, Eduardo L.; Magazzù, Antonio (2008). "Exploring the substellar temperature regime down to ~550 K". Monthly Notices of the Royal Astronomical Society. 391 (1): 320–333. arXiv:0806.0067. Bibcode:2008MNRAS.391..320B. doi:10.1111/j.1365-2966.2008.13885.x. S2CID 1438322.
Luhman, Kevin L.; Esplin, Taran L. (May 2016). "The Spectral Energy Distribution of the Coldest Known Brown Dwarf". The Astronomical Journal. 152 (3): 78. arXiv:1605.06655. Bibcode:2016AJ....152...78L. doi:10.3847/0004-6256/152/3/78. S2CID 118577918.
Burningham, Ben; Smith, L.; Cardoso, C.V.; Lucas, P.W.; Burgasser, Adam J.; Jones, H.R.A.; Smart, R.L. (May 2014). "The discovery of a T6.5 subdwarf". Monthly Notices of the Royal Astronomical Society. 440 (1): 359–364. arXiv:1401.5982. Bibcode:2014MNRAS.440..359B. doi:10.1093/mnras/stu184. ISSN 0035-8711. S2CID 119283917.
Cruz, Kelle L.; Kirkpatrick, J. Davy; Burgasser, Adam J. (February 2009). "Young L dwarfs identified in the field: A preliminary low-gravity, optical spectral Sequence from L0 to L5". The Astronomical Journal. 137 (2): 3345–3357. arXiv:0812.0364. Bibcode:2009AJ....137.3345C. doi:10.1088/0004-6256/137/2/3345. ISSN 0004-6256. S2CID 15376964.
Looper, Dagny L.; Kirkpatrick, J. Davy; Cutri, Roc M.; Barman, Travis; Burgasser, Adam J.; Cushing, Michael C.; Roellig, Thomas; McGovern, Mark R.; McLean, Ian S.; Rice, Emily; Swift, Brandon J. (October 2008). "Discovery of two nearby peculiar L dwarfs from the 2MASS Proper-Motion Survey: Young or metal-rich?". Astrophysical Journal. 686 (1): 528–541. arXiv:0806.1059. Bibcode:2008ApJ...686..528L. doi:10.1086/591025. ISSN 0004-637X. S2CID 18381182.
Kirkpatrick, J. Davy; Looper, Dagny L.; Burgasser, Adam J.; Schurr, Steven D.; Cutri, Roc M.; Cushing, Michael C.; Cruz, Kelle L.; Sweet, Anne C.; Knapp, Gillian R.; Barman, Travis S.; Bochanski, John J. (September 2010). "Discoveries from a near-infrared proper motion survey using multi-epoch Two Micron All-Sky Survey data". Astrophysical Journal Supplement Series. 190 (1): 100–146. arXiv:1008.3591. Bibcode:2010ApJS..190..100K. doi:10.1088/0067-0049/190/1/100. ISSN 0067-0049. S2CID 118435904.
Faherty, Jacqueline K.; Riedel, Adric R.; Cruz, Kelle L.; Gagne, Jonathan; Filippazzo, Joseph C.; Lambrides, Erini; Fica, Haley; Weinberger, Alycia; Thorstensen, John R.; Tinney, C.G.; Baldassare, Vivienne (July 2016). "Population properties of brown dwarf analogs to exoplanets". Astrophysical Journal Supplement Series. 225 (1): 10. arXiv:1605.07927. Bibcode:2016ApJS..225...10F. doi:10.3847/0067-0049/225/1/10. ISSN 0067-0049. S2CID 118446190.
Córsico, A. H.; Althaus, L. G. (2004). "The rate of period change in pulsating DB-white dwarf stars". Astronomy and Astrophysics. 428: 159–170. arXiv:astro-ph/0408237. Bibcode:2004A&A...428..159C. doi:10.1051/0004-6361:20041372. S2CID 14653913.
Apellániz, J. Maíz; Barbá, R. H.; Aranda, R. Fernández; González, M. Pantaleoni; Bellido, P. Crespo; Sota, A.; Alfaro, E. J. (1 January 2022). "The Villafranca catalog of Galactic OB groups – II. From Gaia DR2 to EDR3 and ten new systems with O stars". Astronomy & Astrophysics. 657: A131. arXiv:2110.01464. Bibcode:2022A&A...657A.131M. doi:10.1051/0004-6361/202142364. ISSN 0004-6361.
Massey, Philip; Neugent, Kathryn F.; Smart, Brianna M. (1 September 2016). "A spectroscopic survey of massive stars in M31 AND M33*". The Astronomical Journal. 152 (3): 62. arXiv:1604.00112. Bibcode:2016AJ....152...62M. doi:10.3847/0004-6256/152/3/62. ISSN 0004-6256.
Yakovlev, D. G.; Kaminker, A. D.; Haensel, P.; Gnedin, O. Y. (2002). "The cooling neutron star in 3C 58". Astronomy & Astrophysics. 389: L24 – L27. arXiv:astro-ph/0204233. Bibcode:2002A&A...389L..24Y. doi:10.1051/0004-6361:20020699. S2CID 6247160.

aspbooks.org (Global: low place; English: low place)

Garrison, R. F. (1994). "A Hierarchy of Standards for the MK Process" (PDF). In Corbally, C. J.; Gray, R. O.; Garrison, R. F. (eds.). The MK Process at 50 Years: A Powerful Tool for Astrophysical Insight. Astronomical Society of the Pacific conference series. Vol. 60. San Francisco: Astronomical Society of the Pacific. pp. 3–14. ISBN 978-1-58381-396-6. OCLC 680222523.

bnf.fr (Global: 124^th place; English: 544^th place)

gallica.bnf.fr

Analyse spectrale de la lumière de quelques étoiles, et nouvelles observations sur les taches solaires, P. Secchi, Comptes Rendus des Séances de l'Académie des Sciences 63 (July–December 1866), pp. 364–368.
Nouvelles recherches sur l'analyse spectrale de la lumière des étoiles, P. Secchi, Comptes Rendus des Séances de l'Académie des Sciences 63 (July–December 1866), pp. 621–628.

books.google.com (Global: 3^rd place; English: 3^rd place)

D.S. Hayes; L.E. Pasinetti; A.G. Davis Philip (6 December 2012). Calibration of Fundamental Stellar Quantities: Proceedings of the 111th Symposium of the International Astronomical Union held at Villa Olmo, Como, Italy, May 24–29, 1984. Springer Science & Business Media. pp. 129–. ISBN 978-94-009-5456-4.

caltech.edu (Global: 887^th place; English: 714^th place)

web.ipac.caltech.edu

O'Connell (27 March 2023). "MAGNITUDE AND COLOR SYSTEMS" (PDF). Caltech ASTR 511. Archived (PDF) from the original on 28 March 2023. Retrieved 27 March 2023.

nedipac.caltech.edu

An atlas of stellar spectra, with an outline of spectral classification, W. W. Morgan, P. C. Keenan and E. Kellman, Chicago: The University of Chicago Press, 1943.

authors.library.caltech.edu

Kirkpatrick, J. Davy (2005). "New Spectral Types L and T" (PDF). Annual Review of Astronomy and Astrophysics. 43 (1): 195–246. Bibcode:2005ARA&A..43..195K. doi:10.1146/annurev.astro.42.053102.134017. S2CID 122318616.

csiro.au (Global: 4,114^th place; English: 3,147^th place)

atnf.csiro.au

"The Colour of Stars". Australia Telescope National Facility. 17 October 2018.

outreach.atnf.csiro.au

"The Colour of Stars". Australia Telescope Outreach and Education. 21 December 2004. Archived from the original on 3 December 2013. Retrieved 26 September 2007. — Explains the reason for the difference in color perception.

daviddarling.info (Global: 7,061^st place; English: 6,805^th place)

Darling, David. "late-type star". The Internet Encyclopedia of Science. Retrieved 14 October 2007.

doi.org (Global: 2^nd place; English: 2^nd place)

Jeffery, C. S.; Werner, K.; Kilkenny, D.; Miszalski, B.; Monageng, I.; Snowdon, E. J. (2023). "Hot white dwarfs and pre-white dwarfs discovered with SALT". Monthly Notices of the Royal Astronomical Society. 519 (2): 2321–2330. arXiv:2301.03550. doi:10.1093/mnras/stac3531.
Weidner, Carsten; Vink, Jorick S. (December 2010). "The masses, and the mass discrepancy of O-type stars". Astronomy and Astrophysics. 524. A98. arXiv:1010.2204. Bibcode:2010A&A...524A..98W. doi:10.1051/0004-6361/201014491. S2CID 118836634.
Baraffe, I.; Chabrier, G.; Barman, T. S.; Allard, F.; Hauschildt, P. H. (May 2003). "Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 209458". Astronomy and Astrophysics. 402 (2): 701–712. arXiv:astro-ph/0302293. Bibcode:2003A&A...402..701B. doi:10.1051/0004-6361:20030252. S2CID 15838318.
Sota, A.; Maíz Apellániz, J.; Morrell, N. I.; Barbá, R. H.; Walborn, N. R.; et al. (March 2014). "The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars". The Astrophysical Journal Supplement Series. 211 (1). 10. arXiv:1312.6222. Bibcode:2014ApJS..211...10S. doi:10.1088/0067-0049/211/1/10. S2CID 118847528.
Saha, M. N. (May 1921). "On a Physical Theory of Stellar Spectra". Proceedings of the Royal Society of London. Series A. 99 (697): 135–153. Bibcode:1921RSPSA..99..135S. doi:10.1098/rspa.1921.0029.
Morgan, William Wilson; Keenan, Philip Childs (1973). "Spectral Classification". Annual Review of Astronomy and Astrophysics. 11: 29–50. Bibcode:1973ARA&A..11...29M. doi:10.1146/annurev.aa.11.090173.000333.
Caballero-Nieves, S. M.; Nelan, E. P.; Gies, D. R.; Wallace, D. J.; DeGioia-Eastwood, K.; et al. (February 2014). "A High Angular Resolution Survey of Massive Stars in Cygnus OB2: Results from the Hubble Space Telescope Fine Guidance Sensors". The Astronomical Journal. 147 (2). 40. arXiv:1311.5087. Bibcode:2014AJ....147...40C. doi:10.1088/0004-6256/147/2/40. S2CID 22036552.
Prinja, R. K.; Massa, D. L. (October 2010). "Signature of wide-spread clumping in B supergiant winds". Astronomy and Astrophysics. 521. L55. arXiv:1007.2744. Bibcode:2010A&A...521L..55P. doi:10.1051/0004-6361/201015252. S2CID 59151633.
Gray, David F. (November 2010). "Photospheric Variations of the Supergiant γ Cyg". The Astronomical Journal. 140 (5): 1329–1336. Bibcode:2010AJ....140.1329G. doi:10.1088/0004-6256/140/5/1329.
Nazé, Y. (November 2009). "Hot stars observed by XMM-Newton. I. The catalog and the properties of OB stars". Astronomy and Astrophysics. 506 (2): 1055–1064. arXiv:0908.1461. Bibcode:2009A&A...506.1055N. doi:10.1051/0004-6361/200912659. S2CID 17317459.
Lyubimkov, Leonid S.; Lambert, David L.; Rostopchin, Sergey I.; Rachkovskaya, Tamara M.; Poklad, Dmitry B. (February 2010). "Accurate fundamental parameters for A-, F- and G-type Supergiants in the solar neighbourhood". Monthly Notices of the Royal Astronomical Society. 402 (2): 1369–1379. arXiv:0911.1335. Bibcode:2010MNRAS.402.1369L. doi:10.1111/j.1365-2966.2009.15979.x. S2CID 119096173.
Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Robinson, P. E. (October 2003). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I". The Astronomical Journal. 126 (4): 2048–2059. arXiv:astro-ph/0308182. Bibcode:2003AJ....126.2048G. doi:10.1086/378365. S2CID 119417105.
Shenavrin, V. I.; Taranova, O. G.; Nadzhip, A. E. (January 2011). "Search for and study of hot circumstellar dust envelopes". Astronomy Reports. 55 (1): 31–81. Bibcode:2011ARep...55...31S. doi:10.1134/S1063772911010070. S2CID 122700080.
Cenarro, A. J.; Peletier, R. F.; Sanchez-Blazquez, P.; Selam, S. O.; Toloba, E.; Cardiel, N.; Falcon-Barroso, J.; Gorgas, J.; Jimenez-Vicente, J.; Vazdekis, A. (January 2007). "Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters". Monthly Notices of the Royal Astronomical Society. 374 (2): 664–690. arXiv:astro-ph/0611618. Bibcode:2007MNRAS.374..664C. doi:10.1111/j.1365-2966.2006.11196.x. S2CID 119428437.
Sion, Edward M.; Holberg, J. B.; Oswalt, Terry D.; McCook, George P.; Wasatonic, Richard (December 2009). "The White Dwarfs Within 20 Parsecs of the Sun: Kinematics and Statistics". The Astronomical Journal. 138 (6): 1681–1689. arXiv:0910.1288. Bibcode:2009AJ....138.1681S. doi:10.1088/0004-6256/138/6/1681. S2CID 119284418.
Arias, Julia I.; et al. (August 2016). "Spectral Classification and Properties of the OVz Stars in the Galactic O Star Spectroscopic Survey (GOSSS)". The Astronomical Journal. 152 (2): 31. arXiv:1604.03842. Bibcode:2016AJ....152...31A. doi:10.3847/0004-6256/152/2/31. S2CID 119259952.
Maíz Apellániz, J.; Walborn, Nolan R.; Morrell, N. I.; Niemela, V. S.; Nelan, E. P. (2007). "Pismis 24-1: The Stellar Upper Mass Limit Preserved". The Astrophysical Journal. 660 (2): 1480–1485. arXiv:astro-ph/0612012. Bibcode:2007ApJ...660.1480M. doi:10.1086/513098. S2CID 15936535.
Walborn, Nolan R.; Sota, Alfredo; Maíz Apellániz, Jesús; Alfaro, Emilio J.; Morrell, Nidia I.; Barbá, Rodolfo H.; Arias, Julia I.; Gamen, Roberto C. (2010). "Early Results from the Galactic O-Star Spectroscopic Survey: C III Emission Lines in of Spectra". The Astrophysical Journal Letters. 711 (2): L143. arXiv:1002.3293. Bibcode:2010ApJ...711L.143W. doi:10.1088/2041-8205/711/2/L143. S2CID 119122481.
Fariña, Cecilia; Bosch, Guillermo L.; Morrell, Nidia I.; Barbá, Rodolfo H.; Walborn, Nolan R. (2009). "Spectroscopic Study of the N159/N160 Complex in the Large Magellanic Cloud". The Astronomical Journal. 138 (2): 510–516. arXiv:0907.1033. Bibcode:2009AJ....138..510F. doi:10.1088/0004-6256/138/2/510. S2CID 18844754.
Rauw, G.; Manfroid, J.; Gosset, E.; Nazé, Y.; Sana, H.; De Becker, M.; Foellmi, C.; Moffat, A. F. J. (2007). "Early-type stars in the core of the young open cluster Westerlund 2". Astronomy and Astrophysics. 463 (3): 981–991. arXiv:astro-ph/0612622. Bibcode:2007A&A...463..981R. doi:10.1051/0004-6361:20066495. S2CID 17776145.
Crowther, Paul A. (2007). "Physical Properties of Wolf-Rayet Stars". Annual Review of Astronomy & Astrophysics. 45 (1): 177–219. arXiv:astro-ph/0610356. Bibcode:2007ARA&A..45..177C. doi:10.1146/annurev.astro.45.051806.110615. S2CID 1076292.
Rountree Lesh, J. (1968). "The Kinematics of the Gould Belt: An Expanding Group?". The Astrophysical Journal Supplement Series. 17: 371. Bibcode:1968ApJS...17..371L. doi:10.1086/190179.
Nassau, J. J.; Seyfert, Carl K. (March 1946). "Spectra of BD Stars Within Five Degrees of the North Pole". Astrophysical Journal. 103: 117. Bibcode:1946ApJ...103..117N. doi:10.1086/144796.
Sandage, A. (December 1969). "New subdwarfs. II. Radial velocities, photometry, and preliminary space motions for 112 stars with large proper motion". Astrophysical Journal. 158: 1115. Bibcode:1969ApJ...158.1115S. doi:10.1086/150271.
Norris, Jackson M.; Wright, Jason T.; Wade, Richard A.; Mahadevan, Suvrath; Gettel, Sara (December 2011). "Non-detection of the Putative Substellar Companion to HD 149382". The Astrophysical Journal. 743 (1). 88. arXiv:1110.1384. Bibcode:2011ApJ...743...88N. doi:10.1088/0004-637X/743/1/88. S2CID 118337277.
Walborn, N. R. (1971). "Some Spectroscopic Characteristics of the OB Stars: An Investigation of the Space Distribution of Certain OB Stars and the Reference Frame of the Classification". The Astrophysical Journal Supplement Series. 23: 257. Bibcode:1971ApJS...23..257W. doi:10.1086/190239.
Walborn, Nolan R.; Howarth, Ian D.; Lennon, Daniel J.; Massey, Philip; Oey, M. S.; Moffat, Anthony F. J.; Skalkowski, Gwen; Morrell, Nidia I.; Drissen, Laurent; Parker, Joel Wm. (2002). "A New Spectral Classification System for the Earliest O Stars: Definition of Type O2" (PDF). The Astronomical Journal. 123 (5): 2754–2771. Bibcode:2002AJ....123.2754W. doi:10.1086/339831. S2CID 122127697.
Slettebak, Arne (July 1988). "The Be Stars". Publications of the Astronomical Society of the Pacific. 100: 770–784. Bibcode:1988PASP..100..770S. doi:10.1086/132234.
Morgan, W. W.; Keenan, P. C. (1973). "Spectral Classification". Annual Review of Astronomy and Astrophysics. 11: 29. Bibcode:1973ARA&A..11...29M. doi:10.1146/annurev.aa.11.090173.000333.
Gray, R. O; Garrison, R. F (1989). "The early F-type stars - Refined classification, confrontation with Stromgren photometry, and the effects of rotation". Astrophysical Journal Supplement Series. 69: 301. Bibcode:1989ApJS...69..301G. doi:10.1086/191315.
Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373. S2CID 123149047.
Figer, Donald F.; McLean, Ian S.; Najarro, Francisco (1997). "AK-Band Spectral Atlas of Wolf-Rayet Stars". The Astrophysical Journal. 486 (1): 420–434. Bibcode:1997ApJ...486..420F. doi:10.1086/304488.
Tinkler, C. M.; Lamers, H. J. G. L. M. (2002). "Mass-loss rates of H-rich central stars of planetary nebulae as distance indicators?". Astronomy and Astrophysics. 384 (3): 987–998. Bibcode:2002A&A...384..987T. doi:10.1051/0004-6361:20020061.
Miszalski, B.; Crowther, P. A.; De Marco, O.; Köppen, J.; Moffat, A. F. J.; Acker, A.; Hillwig, T. C. (2012). "IC 4663: The first unambiguous [WN] Wolf-Rayet central star of a planetary nebula". Monthly Notices of the Royal Astronomical Society. 423 (1): 934–947. arXiv:1203.3303. Bibcode:2012MNRAS.423..934M. doi:10.1111/j.1365-2966.2012.20929.x. S2CID 10264296.
Crowther, P. A.; Walborn, N. R. (2011). "Spectral classification of O2-3.5 If*/WN5-7 stars". Monthly Notices of the Royal Astronomical Society. 416 (2): 1311–1323. arXiv:1105.4757. Bibcode:2011MNRAS.416.1311C. doi:10.1111/j.1365-2966.2011.19129.x. S2CID 118455138.
Kirkpatrick, J. Davy; Reid, I. Neill; Liebert, James; Cutri, Roc M.; Nelson, Brant; Beichman, Charles A.; Dahn, Conard C.; Monet, David G.; Gizis, John E.; Skrutskie, Michael F. (10 July 1999). "Dwarfs Cooler than M: the Definition of Spectral Type L Using Discovery from the 2-µ ALL-SKY Survey (2MASS)". The Astrophysical Journal. 519 (2): 802–833. Bibcode:1999ApJ...519..802K. doi:10.1086/307414.
Kirkpatrick, J. Davy (2005). "New Spectral Types L and T" (PDF). Annual Review of Astronomy and Astrophysics. 43 (1): 195–246. Bibcode:2005ARA&A..43..195K. doi:10.1146/annurev.astro.42.053102.134017. S2CID 122318616.
Kirkpatrick, J. Davy; Barman, Travis S.; Burgasser, Adam J.; McGovern, Mark R.; McLean, Ian S.; Tinney, Christopher G.; Lowrance, Patrick J. (2006). "Discovery of a Very Young Field L Dwarf, 2MASS J01415823−4633574". The Astrophysical Journal. 639 (2): 1120–1128. arXiv:astro-ph/0511462. Bibcode:2006ApJ...639.1120K. doi:10.1086/499622. S2CID 13075577.
Kirkpatrick, J. Davy; Cushing, Michael C.; Gelino, Christopher R.; Beichman, Charles A.; Tinney, C. G.; Faherty, Jacqueline K.; Schneider, Adam; Mace, Gregory N. (2013). "Discovery of the Y1 Dwarf WISE J064723.23-623235.5". The Astrophysical Journal. 776 (2): 128. arXiv:1308.5372. Bibcode:2013ApJ...776..128K. doi:10.1088/0004-637X/776/2/128. S2CID 6230841.
Deacon, N. R.; Hambly, N. C. (2006). "Y-Spectral class for Ultra-Cool Dwarfs". Monthly Notices of the Royal Astronomical Society. 371: 1722–1730. arXiv:astro-ph/0607305. doi:10.1111/j.1365-2966.2006.10795.x. S2CID 14081778.
Zuckerman, B.; Song, I. (2009). "The minimum Jeans mass, brown dwarf companion IMF, and predictions for detection of Y-type dwarfs". Astronomy and Astrophysics. 493 (3): 1149–1154. arXiv:0811.0429. Bibcode:2009A&A...493.1149Z. doi:10.1051/0004-6361:200810038. S2CID 18147550.
Dupuy, T. J.; Kraus, A. L. (2013). "Distances, Luminosities, and Temperatures of the Coldest Known Substellar Objects". Science. 341 (6153): 1492–5. arXiv:1309.1422. Bibcode:2013Sci...341.1492D. doi:10.1126/science.1241917. PMID 24009359. S2CID 30379513.
Leggett, Sandy K.; Cushing, Michael C.; Saumon, Didier; Marley, Mark S.; Roellig, Thomas L.; Warren, Stephen J.; Burningham, Ben; Jones, Hugh R. A.; Kirkpatrick, J. Davy; Lodieu, Nicolas; Lucas, Philip W.; Mainzer, Amy K.; Martín, Eduardo L.; McCaughrean, Mark J.; Pinfield, David J.; Sloan, Gregory C.; Smart, Richard L.; Tamura, Motohide; Van Cleve, Jeffrey E. (2009). "The Physical Properties of Four ~600 K T Dwarfs". The Astrophysical Journal. 695 (2): 1517–1526. arXiv:0901.4093. Bibcode:2009ApJ...695.1517L. doi:10.1088/0004-637X/695/2/1517. S2CID 44050900.
Delorme, Philippe; Delfosse, Xavier; Albert, Loïc; Artigau, Étienne; Forveille, Thierry; Reylé, Céline; Allard, France; Homeier, Derek; Robin, Annie C.; Willott, Chris J.; Liu, Michael C.; Dupuy, Trent J. (2008). "CFBDS J005910.90-011401.3: Reaching the T-Y brown dwarf transition?". Astronomy and Astrophysics. 482 (3): 961–971. arXiv:0802.4387. Bibcode:2008A&A...482..961D. doi:10.1051/0004-6361:20079317. S2CID 847552.
Burningham, Ben; Pinfield, D. J.; Leggett, S. K.; Tamura, M.; Lucas, P. W.; Homeier, D.; Day-Jones, A.; Jones, H. R. A.; Clarke, J. R. A.; Ishii, M.; Kuzuhara, M.; Lodieu, N.; Zapatero-Osorio, María Rosa; Venemans, B. P.; Mortlock, D. J.; Barrado y Navascués, D.; Martin, Eduardo L.; Magazzù, Antonio (2008). "Exploring the substellar temperature regime down to ~550 K". Monthly Notices of the Royal Astronomical Society. 391 (1): 320–333. arXiv:0806.0067. Bibcode:2008MNRAS.391..320B. doi:10.1111/j.1365-2966.2008.13885.x. S2CID 1438322.
Luhman, Kevin L.; Esplin, Taran L. (May 2016). "The Spectral Energy Distribution of the Coldest Known Brown Dwarf". The Astronomical Journal. 152 (3): 78. arXiv:1605.06655. Bibcode:2016AJ....152...78L. doi:10.3847/0004-6256/152/3/78. S2CID 118577918.
Burningham, Ben; Smith, L.; Cardoso, C.V.; Lucas, P.W.; Burgasser, Adam J.; Jones, H.R.A.; Smart, R.L. (May 2014). "The discovery of a T6.5 subdwarf". Monthly Notices of the Royal Astronomical Society. 440 (1): 359–364. arXiv:1401.5982. Bibcode:2014MNRAS.440..359B. doi:10.1093/mnras/stu184. ISSN 0035-8711. S2CID 119283917.
Cruz, Kelle L.; Kirkpatrick, J. Davy; Burgasser, Adam J. (February 2009). "Young L dwarfs identified in the field: A preliminary low-gravity, optical spectral Sequence from L0 to L5". The Astronomical Journal. 137 (2): 3345–3357. arXiv:0812.0364. Bibcode:2009AJ....137.3345C. doi:10.1088/0004-6256/137/2/3345. ISSN 0004-6256. S2CID 15376964.
Looper, Dagny L.; Kirkpatrick, J. Davy; Cutri, Roc M.; Barman, Travis; Burgasser, Adam J.; Cushing, Michael C.; Roellig, Thomas; McGovern, Mark R.; McLean, Ian S.; Rice, Emily; Swift, Brandon J. (October 2008). "Discovery of two nearby peculiar L dwarfs from the 2MASS Proper-Motion Survey: Young or metal-rich?". Astrophysical Journal. 686 (1): 528–541. arXiv:0806.1059. Bibcode:2008ApJ...686..528L. doi:10.1086/591025. ISSN 0004-637X. S2CID 18381182.
Kirkpatrick, J. Davy; Looper, Dagny L.; Burgasser, Adam J.; Schurr, Steven D.; Cutri, Roc M.; Cushing, Michael C.; Cruz, Kelle L.; Sweet, Anne C.; Knapp, Gillian R.; Barman, Travis S.; Bochanski, John J. (September 2010). "Discoveries from a near-infrared proper motion survey using multi-epoch Two Micron All-Sky Survey data". Astrophysical Journal Supplement Series. 190 (1): 100–146. arXiv:1008.3591. Bibcode:2010ApJS..190..100K. doi:10.1088/0067-0049/190/1/100. ISSN 0067-0049. S2CID 118435904.
Faherty, Jacqueline K.; Riedel, Adric R.; Cruz, Kelle L.; Gagne, Jonathan; Filippazzo, Joseph C.; Lambrides, Erini; Fica, Haley; Weinberger, Alycia; Thorstensen, John R.; Tinney, C.G.; Baldassare, Vivienne (July 2016). "Population properties of brown dwarf analogs to exoplanets". Astrophysical Journal Supplement Series. 225 (1): 10. arXiv:1605.07927. Bibcode:2016ApJS..225...10F. doi:10.3847/0067-0049/225/1/10. ISSN 0067-0049. S2CID 118446190.
Keenan, P. C. (1954). "Classification of the S-Type Stars". Astrophysical Journal. 120: 484. Bibcode:1954ApJ...120..484K. doi:10.1086/145937.
Sion, E. M.; Greenstein, J. L.; Landstreet, J. D.; Liebert, James; Shipman, H. L.; Wegner, G. A. (1983). "A proposed new white dwarf spectral classification system". Astrophysical Journal. 269: 253. Bibcode:1983ApJ...269..253S. doi:10.1086/161036.
Córsico, A. H.; Althaus, L. G. (2004). "The rate of period change in pulsating DB-white dwarf stars". Astronomy and Astrophysics. 428: 159–170. arXiv:astro-ph/0408237. Bibcode:2004A&A...428..159C. doi:10.1051/0004-6361:20041372. S2CID 14653913.
McCook, George P.; Sion, Edward M. (1999). "A Catalog of Spectroscopically Identified White Dwarfs". The Astrophysical Journal Supplement Series. 121 (1): 1–130. Bibcode:1999ApJS..121....1M. CiteSeerX 10.1.1.565.5507. doi:10.1086/313186. S2CID 122286998.
Apellániz, J. Maíz; Barbá, R. H.; Aranda, R. Fernández; González, M. Pantaleoni; Bellido, P. Crespo; Sota, A.; Alfaro, E. J. (1 January 2022). "The Villafranca catalog of Galactic OB groups – II. From Gaia DR2 to EDR3 and ten new systems with O stars". Astronomy & Astrophysics. 657: A131. arXiv:2110.01464. Bibcode:2022A&A...657A.131M. doi:10.1051/0004-6361/202142364. ISSN 0004-6361.
Massey, Philip; Neugent, Kathryn F.; Smart, Brianna M. (1 September 2016). "A spectroscopic survey of massive stars in M31 AND M33*". The Astronomical Journal. 152 (3): 62. arXiv:1604.00112. Bibcode:2016AJ....152...62M. doi:10.3847/0004-6256/152/3/62. ISSN 0004-6256.
Yakovlev, D. G.; Kaminker, A. D.; Haensel, P.; Gnedin, O. Y. (2002). "The cooling neutron star in 3C 58". Astronomy & Astrophysics. 389: L24 – L27. arXiv:astro-ph/0204233. Bibcode:2002A&A...389L..24Y. doi:10.1051/0004-6361:20020699. S2CID 6247160.

eso.org (Global: 3,034^th place; English: 2,650^th place)

European Southern Observatory. "A Very Cool Pair of Brown Dwarfs", 23 March 2011

eudesign.com (Global: low place; English: low place)

"Spectral classification of stars (OBAFGKM)". www.eudesign.com. Retrieved 6 April 2019.

gsu.edu (Global: 1,911^th place; English: 1,817^th place)

astro.gsu.edu

"THE 100 NEAREST STAR SYSTEMS". www.astro.gsu.edu. Retrieved 13 April 2022.

harvard.edu (Global: 18^th place; English: 17^th place)

ui.adsabs.harvard.edu

Habets, G. M. H. J.; Heinze, J. R. W. (November 1981). "Empirical bolometric corrections for the main-sequence". Astronomy and Astrophysics Supplement Series. 46: 193–237 (Tables VII and VIII). Bibcode:1981A&AS...46..193H. – Luminosities are derived from M_bol figures, using M_bol(☉)=4.75.
Weidner, Carsten; Vink, Jorick S. (December 2010). "The masses, and the mass discrepancy of O-type stars". Astronomy and Astrophysics. 524. A98. arXiv:1010.2204. Bibcode:2010A&A...524A..98W. doi:10.1051/0004-6361/201014491. S2CID 118836634.
Baraffe, I.; Chabrier, G.; Barman, T. S.; Allard, F.; Hauschildt, P. H. (May 2003). "Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 209458". Astronomy and Astrophysics. 402 (2): 701–712. arXiv:astro-ph/0302293. Bibcode:2003A&A...402..701B. doi:10.1051/0004-6361:20030252. S2CID 15838318.
Ledrew, Glenn (February 2001). "The Real Starry Sky". Journal of the Royal Astronomical Society of Canada. 95: 32. Bibcode:2001JRASC..95...32L.
Sota, A.; Maíz Apellániz, J.; Morrell, N. I.; Barbá, R. H.; Walborn, N. R.; et al. (March 2014). "The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars". The Astrophysical Journal Supplement Series. 211 (1). 10. arXiv:1312.6222. Bibcode:2014ApJS..211...10S. doi:10.1088/0067-0049/211/1/10. S2CID 118847528.
Russell, Henry Norris (March 1914). "Relations Between the Spectra and Other Characteristics of the Stars". Popular Astronomy. Vol. 22. pp. 275–294. Bibcode:1914PA.....22..275R.
Saha, M. N. (May 1921). "On a Physical Theory of Stellar Spectra". Proceedings of the Royal Society of London. Series A. 99 (697): 135–153. Bibcode:1921RSPSA..99..135S. doi:10.1098/rspa.1921.0029.
Payne, Cecilia Helena (1925). Stellar Atmospheres; a Contribution to the Observational Study of High Temperature in the Reversing Layers of Stars (Ph.D). Radcliffe College. Bibcode:1925PhDT.........1P.
Morgan, William Wilson; Keenan, Philip Childs; Kellman, Edith (1943). An atlas of stellar spectra, with an outline of spectral classification. The University of Chicago Press. Bibcode:1943assw.book.....M. OCLC 1806249.
Morgan, William Wilson; Keenan, Philip Childs (1973). "Spectral Classification". Annual Review of Astronomy and Astrophysics. 11: 29–50. Bibcode:1973ARA&A..11...29M. doi:10.1146/annurev.aa.11.090173.000333.
Caballero-Nieves, S. M.; Nelan, E. P.; Gies, D. R.; Wallace, D. J.; DeGioia-Eastwood, K.; et al. (February 2014). "A High Angular Resolution Survey of Massive Stars in Cygnus OB2: Results from the Hubble Space Telescope Fine Guidance Sensors". The Astronomical Journal. 147 (2). 40. arXiv:1311.5087. Bibcode:2014AJ....147...40C. doi:10.1088/0004-6256/147/2/40. S2CID 22036552.
Prinja, R. K.; Massa, D. L. (October 2010). "Signature of wide-spread clumping in B supergiant winds". Astronomy and Astrophysics. 521. L55. arXiv:1007.2744. Bibcode:2010A&A...521L..55P. doi:10.1051/0004-6361/201015252. S2CID 59151633.
Gray, David F. (November 2010). "Photospheric Variations of the Supergiant γ Cyg". The Astronomical Journal. 140 (5): 1329–1336. Bibcode:2010AJ....140.1329G. doi:10.1088/0004-6256/140/5/1329.
Nazé, Y. (November 2009). "Hot stars observed by XMM-Newton. I. The catalog and the properties of OB stars". Astronomy and Astrophysics. 506 (2): 1055–1064. arXiv:0908.1461. Bibcode:2009A&A...506.1055N. doi:10.1051/0004-6361/200912659. S2CID 17317459.
Lyubimkov, Leonid S.; Lambert, David L.; Rostopchin, Sergey I.; Rachkovskaya, Tamara M.; Poklad, Dmitry B. (February 2010). "Accurate fundamental parameters for A-, F- and G-type Supergiants in the solar neighbourhood". Monthly Notices of the Royal Astronomical Society. 402 (2): 1369–1379. arXiv:0911.1335. Bibcode:2010MNRAS.402.1369L. doi:10.1111/j.1365-2966.2009.15979.x. S2CID 119096173.
Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Robinson, P. E. (October 2003). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I". The Astronomical Journal. 126 (4): 2048–2059. arXiv:astro-ph/0308182. Bibcode:2003AJ....126.2048G. doi:10.1086/378365. S2CID 119417105.
Shenavrin, V. I.; Taranova, O. G.; Nadzhip, A. E. (January 2011). "Search for and study of hot circumstellar dust envelopes". Astronomy Reports. 55 (1): 31–81. Bibcode:2011ARep...55...31S. doi:10.1134/S1063772911010070. S2CID 122700080.
Cenarro, A. J.; Peletier, R. F.; Sanchez-Blazquez, P.; Selam, S. O.; Toloba, E.; Cardiel, N.; Falcon-Barroso, J.; Gorgas, J.; Jimenez-Vicente, J.; Vazdekis, A. (January 2007). "Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters". Monthly Notices of the Royal Astronomical Society. 374 (2): 664–690. arXiv:astro-ph/0611618. Bibcode:2007MNRAS.374..664C. doi:10.1111/j.1365-2966.2006.11196.x. S2CID 119428437.
Sion, Edward M.; Holberg, J. B.; Oswalt, Terry D.; McCook, George P.; Wasatonic, Richard (December 2009). "The White Dwarfs Within 20 Parsecs of the Sun: Kinematics and Statistics". The Astronomical Journal. 138 (6): 1681–1689. arXiv:0910.1288. Bibcode:2009AJ....138.1681S. doi:10.1088/0004-6256/138/6/1681. S2CID 119284418.
Arias, Julia I.; et al. (August 2016). "Spectral Classification and Properties of the OVz Stars in the Galactic O Star Spectroscopic Survey (GOSSS)". The Astronomical Journal. 152 (2): 31. arXiv:1604.03842. Bibcode:2016AJ....152...31A. doi:10.3847/0004-6256/152/2/31. S2CID 119259952.
Maíz Apellániz, J.; Walborn, Nolan R.; Morrell, N. I.; Niemela, V. S.; Nelan, E. P. (2007). "Pismis 24-1: The Stellar Upper Mass Limit Preserved". The Astrophysical Journal. 660 (2): 1480–1485. arXiv:astro-ph/0612012. Bibcode:2007ApJ...660.1480M. doi:10.1086/513098. S2CID 15936535.
Walborn, Nolan R.; Sota, Alfredo; Maíz Apellániz, Jesús; Alfaro, Emilio J.; Morrell, Nidia I.; Barbá, Rodolfo H.; Arias, Julia I.; Gamen, Roberto C. (2010). "Early Results from the Galactic O-Star Spectroscopic Survey: C III Emission Lines in of Spectra". The Astrophysical Journal Letters. 711 (2): L143. arXiv:1002.3293. Bibcode:2010ApJ...711L.143W. doi:10.1088/2041-8205/711/2/L143. S2CID 119122481.
Fariña, Cecilia; Bosch, Guillermo L.; Morrell, Nidia I.; Barbá, Rodolfo H.; Walborn, Nolan R. (2009). "Spectroscopic Study of the N159/N160 Complex in the Large Magellanic Cloud". The Astronomical Journal. 138 (2): 510–516. arXiv:0907.1033. Bibcode:2009AJ....138..510F. doi:10.1088/0004-6256/138/2/510. S2CID 18844754.
Rauw, G.; Manfroid, J.; Gosset, E.; Nazé, Y.; Sana, H.; De Becker, M.; Foellmi, C.; Moffat, A. F. J. (2007). "Early-type stars in the core of the young open cluster Westerlund 2". Astronomy and Astrophysics. 463 (3): 981–991. arXiv:astro-ph/0612622. Bibcode:2007A&A...463..981R. doi:10.1051/0004-6361:20066495. S2CID 17776145.
Crowther, Paul A. (2007). "Physical Properties of Wolf-Rayet Stars". Annual Review of Astronomy & Astrophysics. 45 (1): 177–219. arXiv:astro-ph/0610356. Bibcode:2007ARA&A..45..177C. doi:10.1146/annurev.astro.45.051806.110615. S2CID 1076292.
Rountree Lesh, J. (1968). "The Kinematics of the Gould Belt: An Expanding Group?". The Astrophysical Journal Supplement Series. 17: 371. Bibcode:1968ApJS...17..371L. doi:10.1086/190179.
Pickering, Edward C. (1890). "The Draper Catalogue of stellar spectra photographed with the 8-inch Bache telescope as a part of the Henry Draper memorial". Annals of Harvard College Observatory. 27: 1. Bibcode:1890AnHar..27....1P.
Payne, Cecilia H. (1930). "Classification of the O Stars". Harvard College Observatory Bulletin. 878: 1. Bibcode:1930BHarO.878....1P.
Maury, Antonia C.; Pickering, Edward C. (1897). "Spectra of bright stars photographed with the 11 inch Draper Telescope as part of the Henry Draper Memorial". Annals of Harvard College Observatory. 28: 1. Bibcode:1897AnHar..28....1M.
Cannon, Annie J.; Pickering, Edward C. (1901). "Spectra of bright southern stars photographed with the 13 inch Boyden telescope as part of the Henry Draper Memorial". Annals of Harvard College Observatory. 28: 129. Bibcode:1901AnHar..28..129C.
Cannon, Annie Jump; Pickering, Edward Charles (1912). "Classification of 1,688 southern stars by means of their spectra". Annals of the Astronomical Observatory of Harvard College. 56 (5): 115. Bibcode:1912AnHar..56..115C.
Nassau, J. J.; Seyfert, Carl K. (March 1946). "Spectra of BD Stars Within Five Degrees of the North Pole". Astrophysical Journal. 103: 117. Bibcode:1946ApJ...103..117N. doi:10.1086/144796.
FitzGerald, M. Pim (October 1969). "Comparison Between Spectral-Luminosity Classes on the Mount Wilson and Morgan–Keenan Systems of Classification". Journal of the Royal Astronomical Society of Canada. 63: 251. Bibcode:1969JRASC..63..251P.
Sandage, A. (December 1969). "New subdwarfs. II. Radial velocities, photometry, and preliminary space motions for 112 stars with large proper motion". Astrophysical Journal. 158: 1115. Bibcode:1969ApJ...158.1115S. doi:10.1086/150271.
Norris, Jackson M.; Wright, Jason T.; Wade, Richard A.; Mahadevan, Suvrath; Gettel, Sara (December 2011). "Non-detection of the Putative Substellar Companion to HD 149382". The Astrophysical Journal. 743 (1). 88. arXiv:1110.1384. Bibcode:2011ApJ...743...88N. doi:10.1088/0004-637X/743/1/88. S2CID 118337277.
Walborn, N. R. (2008). "Multiwavelength Systematics of OB Spectra". Massive Stars: Fundamental Parameters and Circumstellar Interactions (Eds. P. Benaglia. 33: 5. Bibcode:2008RMxAC..33....5W.
Walborn, N. R. (1971). "Some Spectroscopic Characteristics of the OB Stars: An Investigation of the Space Distribution of Certain OB Stars and the Reference Frame of the Classification". The Astrophysical Journal Supplement Series. 23: 257. Bibcode:1971ApJS...23..257W. doi:10.1086/190239.
Morgan, W. W.; Abt, Helmut A.; Tapscott, J. W. (1978). "Revised MK Spectral Atlas for stars earlier than the sun". Williams Bay: Yerkes Observatory. Bibcode:1978rmsa.book.....M.
Walborn, Nolan R.; Howarth, Ian D.; Lennon, Daniel J.; Massey, Philip; Oey, M. S.; Moffat, Anthony F. J.; Skalkowski, Gwen; Morrell, Nidia I.; Drissen, Laurent; Parker, Joel Wm. (2002). "A New Spectral Classification System for the Earliest O Stars: Definition of Type O2" (PDF). The Astronomical Journal. 123 (5): 2754–2771. Bibcode:2002AJ....123.2754W. doi:10.1086/339831. S2CID 122127697.
Slettebak, Arne (July 1988). "The Be Stars". Publications of the Astronomical Society of the Pacific. 100: 770–784. Bibcode:1988PASP..100..770S. doi:10.1086/132234.
Morgan, W. W.; Keenan, P. C. (1973). "Spectral Classification". Annual Review of Astronomy and Astrophysics. 11: 29. Bibcode:1973ARA&A..11...29M. doi:10.1146/annurev.aa.11.090173.000333.
Morgan, W. W.; Abt, Helmut A.; Tapscott, J. W. (1978). Revised MK Spectral Atlas for stars earlier than the sun. Yerkes Observatory, University of Chicago. Bibcode:1978rmsa.book.....M.{{cite book}}: CS1 maint: location missing publisher (link)
Gray, R. O; Garrison, R. F (1989). "The early F-type stars - Refined classification, confrontation with Stromgren photometry, and the effects of rotation". Astrophysical Journal Supplement Series. 69: 301. Bibcode:1989ApJS...69..301G. doi:10.1086/191315.
Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373. S2CID 123149047.
Nieuwenhuijzen, H.; De Jager, C. (2000). "Checking the yellow evolutionary void. Three evolutionary critical Hypergiants: HD 33579, HR 8752 & IRC +10420". Astronomy and Astrophysics. 353: 163. Bibcode:2000A&A...353..163N.
Payne, Cecilia H. (1930). "Classification of the O Stars". Harvard College Observatory Bulletin. 878: 1. Bibcode:1930BHarO.878....1P.
Figer, Donald F.; McLean, Ian S.; Najarro, Francisco (1997). "AK-Band Spectral Atlas of Wolf-Rayet Stars". The Astrophysical Journal. 486 (1): 420–434. Bibcode:1997ApJ...486..420F. doi:10.1086/304488.
Kingsburgh, R. L.; Barlow, M. J.; Storey, P. J. (1995). "Properties of the WO Wolf-Rayet stars". Astronomy and Astrophysics. 295: 75. Bibcode:1995A&A...295...75K.
Tinkler, C. M.; Lamers, H. J. G. L. M. (2002). "Mass-loss rates of H-rich central stars of planetary nebulae as distance indicators?". Astronomy and Astrophysics. 384 (3): 987–998. Bibcode:2002A&A...384..987T. doi:10.1051/0004-6361:20020061.
Miszalski, B.; Crowther, P. A.; De Marco, O.; Köppen, J.; Moffat, A. F. J.; Acker, A.; Hillwig, T. C. (2012). "IC 4663: The first unambiguous [WN] Wolf-Rayet central star of a planetary nebula". Monthly Notices of the Royal Astronomical Society. 423 (1): 934–947. arXiv:1203.3303. Bibcode:2012MNRAS.423..934M. doi:10.1111/j.1365-2966.2012.20929.x. S2CID 10264296.
Crowther, P. A.; Walborn, N. R. (2011). "Spectral classification of O2-3.5 If*/WN5-7 stars". Monthly Notices of the Royal Astronomical Society. 416 (2): 1311–1323. arXiv:1105.4757. Bibcode:2011MNRAS.416.1311C. doi:10.1111/j.1365-2966.2011.19129.x. S2CID 118455138.
Kirkpatrick, J. D. (2008). "Outstanding Issues in Our Understanding of L, T, and Y Dwarfs". 14th Cambridge Workshop on Cool Stars. 384: 85. arXiv:0704.1522. Bibcode:2008ASPC..384...85K.
Kirkpatrick, J. Davy; Reid, I. Neill; Liebert, James; Cutri, Roc M.; Nelson, Brant; Beichman, Charles A.; Dahn, Conard C.; Monet, David G.; Gizis, John E.; Skrutskie, Michael F. (10 July 1999). "Dwarfs Cooler than M: the Definition of Spectral Type L Using Discovery from the 2-µ ALL-SKY Survey (2MASS)". The Astrophysical Journal. 519 (2): 802–833. Bibcode:1999ApJ...519..802K. doi:10.1086/307414.
Kirkpatrick, J. Davy (2005). "New Spectral Types L and T" (PDF). Annual Review of Astronomy and Astrophysics. 43 (1): 195–246. Bibcode:2005ARA&A..43..195K. doi:10.1146/annurev.astro.42.053102.134017. S2CID 122318616.
Kirkpatrick, J. Davy; Barman, Travis S.; Burgasser, Adam J.; McGovern, Mark R.; McLean, Ian S.; Tinney, Christopher G.; Lowrance, Patrick J. (2006). "Discovery of a Very Young Field L Dwarf, 2MASS J01415823−4633574". The Astrophysical Journal. 639 (2): 1120–1128. arXiv:astro-ph/0511462. Bibcode:2006ApJ...639.1120K. doi:10.1086/499622. S2CID 13075577.
Kirkpatrick, J. Davy; Cushing, Michael C.; Gelino, Christopher R.; Beichman, Charles A.; Tinney, C. G.; Faherty, Jacqueline K.; Schneider, Adam; Mace, Gregory N. (2013). "Discovery of the Y1 Dwarf WISE J064723.23-623235.5". The Astrophysical Journal. 776 (2): 128. arXiv:1308.5372. Bibcode:2013ApJ...776..128K. doi:10.1088/0004-637X/776/2/128. S2CID 6230841.
Zuckerman, B.; Song, I. (2009). "The minimum Jeans mass, brown dwarf companion IMF, and predictions for detection of Y-type dwarfs". Astronomy and Astrophysics. 493 (3): 1149–1154. arXiv:0811.0429. Bibcode:2009A&A...493.1149Z. doi:10.1051/0004-6361:200810038. S2CID 18147550.
Dupuy, T. J.; Kraus, A. L. (2013). "Distances, Luminosities, and Temperatures of the Coldest Known Substellar Objects". Science. 341 (6153): 1492–5. arXiv:1309.1422. Bibcode:2013Sci...341.1492D. doi:10.1126/science.1241917. PMID 24009359. S2CID 30379513.
Leggett, Sandy K.; Cushing, Michael C.; Saumon, Didier; Marley, Mark S.; Roellig, Thomas L.; Warren, Stephen J.; Burningham, Ben; Jones, Hugh R. A.; Kirkpatrick, J. Davy; Lodieu, Nicolas; Lucas, Philip W.; Mainzer, Amy K.; Martín, Eduardo L.; McCaughrean, Mark J.; Pinfield, David J.; Sloan, Gregory C.; Smart, Richard L.; Tamura, Motohide; Van Cleve, Jeffrey E. (2009). "The Physical Properties of Four ~600 K T Dwarfs". The Astrophysical Journal. 695 (2): 1517–1526. arXiv:0901.4093. Bibcode:2009ApJ...695.1517L. doi:10.1088/0004-637X/695/2/1517. S2CID 44050900.
Delorme, Philippe; Delfosse, Xavier; Albert, Loïc; Artigau, Étienne; Forveille, Thierry; Reylé, Céline; Allard, France; Homeier, Derek; Robin, Annie C.; Willott, Chris J.; Liu, Michael C.; Dupuy, Trent J. (2008). "CFBDS J005910.90-011401.3: Reaching the T-Y brown dwarf transition?". Astronomy and Astrophysics. 482 (3): 961–971. arXiv:0802.4387. Bibcode:2008A&A...482..961D. doi:10.1051/0004-6361:20079317. S2CID 847552.
Burningham, Ben; Pinfield, D. J.; Leggett, S. K.; Tamura, M.; Lucas, P. W.; Homeier, D.; Day-Jones, A.; Jones, H. R. A.; Clarke, J. R. A.; Ishii, M.; Kuzuhara, M.; Lodieu, N.; Zapatero-Osorio, María Rosa; Venemans, B. P.; Mortlock, D. J.; Barrado y Navascués, D.; Martin, Eduardo L.; Magazzù, Antonio (2008). "Exploring the substellar temperature regime down to ~550 K". Monthly Notices of the Royal Astronomical Society. 391 (1): 320–333. arXiv:0806.0067. Bibcode:2008MNRAS.391..320B. doi:10.1111/j.1365-2966.2008.13885.x. S2CID 1438322.
Luhman, Kevin L.; Esplin, Taran L. (May 2016). "The Spectral Energy Distribution of the Coldest Known Brown Dwarf". The Astronomical Journal. 152 (3): 78. arXiv:1605.06655. Bibcode:2016AJ....152...78L. doi:10.3847/0004-6256/152/3/78. S2CID 118577918.
Burningham, Ben; Smith, L.; Cardoso, C.V.; Lucas, P.W.; Burgasser, Adam J.; Jones, H.R.A.; Smart, R.L. (May 2014). "The discovery of a T6.5 subdwarf". Monthly Notices of the Royal Astronomical Society. 440 (1): 359–364. arXiv:1401.5982. Bibcode:2014MNRAS.440..359B. doi:10.1093/mnras/stu184. ISSN 0035-8711. S2CID 119283917.
Cruz, Kelle L.; Kirkpatrick, J. Davy; Burgasser, Adam J. (February 2009). "Young L dwarfs identified in the field: A preliminary low-gravity, optical spectral Sequence from L0 to L5". The Astronomical Journal. 137 (2): 3345–3357. arXiv:0812.0364. Bibcode:2009AJ....137.3345C. doi:10.1088/0004-6256/137/2/3345. ISSN 0004-6256. S2CID 15376964.
Looper, Dagny L.; Kirkpatrick, J. Davy; Cutri, Roc M.; Barman, Travis; Burgasser, Adam J.; Cushing, Michael C.; Roellig, Thomas; McGovern, Mark R.; McLean, Ian S.; Rice, Emily; Swift, Brandon J. (October 2008). "Discovery of two nearby peculiar L dwarfs from the 2MASS Proper-Motion Survey: Young or metal-rich?". Astrophysical Journal. 686 (1): 528–541. arXiv:0806.1059. Bibcode:2008ApJ...686..528L. doi:10.1086/591025. ISSN 0004-637X. S2CID 18381182.
Kirkpatrick, J. Davy; Looper, Dagny L.; Burgasser, Adam J.; Schurr, Steven D.; Cutri, Roc M.; Cushing, Michael C.; Cruz, Kelle L.; Sweet, Anne C.; Knapp, Gillian R.; Barman, Travis S.; Bochanski, John J. (September 2010). "Discoveries from a near-infrared proper motion survey using multi-epoch Two Micron All-Sky Survey data". Astrophysical Journal Supplement Series. 190 (1): 100–146. arXiv:1008.3591. Bibcode:2010ApJS..190..100K. doi:10.1088/0067-0049/190/1/100. ISSN 0067-0049. S2CID 118435904.
Faherty, Jacqueline K.; Riedel, Adric R.; Cruz, Kelle L.; Gagne, Jonathan; Filippazzo, Joseph C.; Lambrides, Erini; Fica, Haley; Weinberger, Alycia; Thorstensen, John R.; Tinney, C.G.; Baldassare, Vivienne (July 2016). "Population properties of brown dwarf analogs to exoplanets". Astrophysical Journal Supplement Series. 225 (1): 10. arXiv:1605.07927. Bibcode:2016ApJS..225...10F. doi:10.3847/0067-0049/225/1/10. ISSN 0067-0049. S2CID 118446190.
Keenan, P. C. (1954). "Classification of the S-Type Stars". Astrophysical Journal. 120: 484. Bibcode:1954ApJ...120..484K. doi:10.1086/145937.
Sion, E. M.; Greenstein, J. L.; Landstreet, J. D.; Liebert, James; Shipman, H. L.; Wegner, G. A. (1983). "A proposed new white dwarf spectral classification system". Astrophysical Journal. 269: 253. Bibcode:1983ApJ...269..253S. doi:10.1086/161036.
Córsico, A. H.; Althaus, L. G. (2004). "The rate of period change in pulsating DB-white dwarf stars". Astronomy and Astrophysics. 428: 159–170. arXiv:astro-ph/0408237. Bibcode:2004A&A...428..159C. doi:10.1051/0004-6361:20041372. S2CID 14653913.
McCook, George P.; Sion, Edward M. (1999). "A Catalog of Spectroscopically Identified White Dwarfs". The Astrophysical Journal Supplement Series. 121 (1): 1–130. Bibcode:1999ApJS..121....1M. CiteSeerX 10.1.1.565.5507. doi:10.1086/313186. S2CID 122286998.
Apellániz, J. Maíz; Barbá, R. H.; Aranda, R. Fernández; González, M. Pantaleoni; Bellido, P. Crespo; Sota, A.; Alfaro, E. J. (1 January 2022). "The Villafranca catalog of Galactic OB groups – II. From Gaia DR2 to EDR3 and ten new systems with O stars". Astronomy & Astrophysics. 657: A131. arXiv:2110.01464. Bibcode:2022A&A...657A.131M. doi:10.1051/0004-6361/202142364. ISSN 0004-6361.
Massey, Philip; Neugent, Kathryn F.; Smart, Brianna M. (1 September 2016). "A spectroscopic survey of massive stars in M31 AND M33*". The Astronomical Journal. 152 (3): 62. arXiv:1604.00112. Bibcode:2016AJ....152...62M. doi:10.3847/0004-6256/152/3/62. ISSN 0004-6256.
Yakovlev, D. G.; Kaminker, A. D.; Haensel, P.; Gnedin, O. Y. (2002). "The cooling neutron star in 3C 58". Astronomy & Astrophysics. 389: L24 – L27. arXiv:astro-ph/0204233. Bibcode:2002A&A...389L..24Y. doi:10.1051/0004-6361:20020699. S2CID 6247160.

cfa.harvard.edu

"A note on the spectral atlas and spectral classification". Centre de données astronomiques de Strasbourg. Retrieved 2 January 2015.

chandra.harvard.edu

"Pulsating Variable Stars and the Hertzsprung-Russell (H-R) Diagram". Center for Astrophysics | Harvard & Smithsonian. 9 March 2015. Retrieved 23 July 2016.

nasa.gov (Global: 75^th place; English: 83^rd place)

nasa.gov

""Goldilocks" Stars May Be "Just Right" for Finding Habitable Worlds". NASA.com. 7 March 2019. Retrieved 26 August 2021.
"NASA - NASA'S Wise Mission Discovers Coolest Class of Stars". www.nasa.gov. Archived from the original on 14 February 2021. Retrieved 1 November 2019.

science.nasa.gov

"Discovered: Stars as Cool as the Human Body | Science Mission Directorate". science.nasa.gov. Archived from the original on 7 October 2011. Retrieved 12 July 2017.

nih.gov (Global: 4^th place; English: 4^th place)

pubmed.ncbi.nlm.nih.gov

Dupuy, T. J.; Kraus, A. L. (2013). "Distances, Luminosities, and Temperatures of the Coldest Known Substellar Objects". Science. 341 (6153): 1492–5. arXiv:1309.1422. Bibcode:2013Sci...341.1492D. doi:10.1126/science.1241917. PMID 24009359. S2CID 30379513.

oxfordreference.com (Global: 938^th place; English: 658^th place)

"Williamina Fleming". Oxford Reference. Retrieved 10 June 2020.

physicsanduniverse.com (Global: low place; English: low place)

Universe, Physics And (14 June 2013). "The Yerkes spectral classification". Physics and Universe. Retrieved 31 August 2022.

projectcontinua.org (Global: low place; English: low place)

"Williamina Paton Fleming -". www.projectcontinua.org. Retrieved 10 June 2020.
"Antonia Maury". www.projectcontinua.org. Retrieved 10 June 2020.
Hearnshaw, J.B. (17 March 2014). The analysis of starlight: Two centuries of astronomical spectroscopy (2nd ed.). New York, NY. ISBN 978-1-107-03174-6. OCLC 855909920.{{cite book}}: CS1 maint: location missing publisher (link)
Gray, Richard O.; Corbally, Christopher J.; Burgasser, Adam J. (2009). Stellar spectral classification. Princeton, NJ: Princeton University Press. ISBN 978-0-691-12510-7. OCLC 276340686.
"Annie Jump Cannon". www.projectcontinua.org. Retrieved 10 June 2020.

psu.edu (Global: 207^th place; English: 136^th place)

citeseerx.ist.psu.edu

McCook, George P.; Sion, Edward M. (1999). "A Catalog of Spectroscopically Identified White Dwarfs". The Astrophysical Journal Supplement Series. 121 (1): 1–130. Bibcode:1999ApJS..121....1M. CiteSeerX 10.1.1.565.5507. doi:10.1086/313186. S2CID 122286998.

rit.edu (Global: 8,676^th place; English: 6,229^th place)

spiff.rit.edu

"Classification of stellar spectra". spiff.rit.edu. Retrieved 10 June 2020.

semanticscholar.org (Global: 11^th place; English: 8^th place)

api.semanticscholar.org

Weidner, Carsten; Vink, Jorick S. (December 2010). "The masses, and the mass discrepancy of O-type stars". Astronomy and Astrophysics. 524. A98. arXiv:1010.2204. Bibcode:2010A&A...524A..98W. doi:10.1051/0004-6361/201014491. S2CID 118836634.
Baraffe, I.; Chabrier, G.; Barman, T. S.; Allard, F.; Hauschildt, P. H. (May 2003). "Evolutionary models for cool brown dwarfs and extrasolar giant planets. The case of HD 209458". Astronomy and Astrophysics. 402 (2): 701–712. arXiv:astro-ph/0302293. Bibcode:2003A&A...402..701B. doi:10.1051/0004-6361:20030252. S2CID 15838318.
Sota, A.; Maíz Apellániz, J.; Morrell, N. I.; Barbá, R. H.; Walborn, N. R.; et al. (March 2014). "The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars". The Astrophysical Journal Supplement Series. 211 (1). 10. arXiv:1312.6222. Bibcode:2014ApJS..211...10S. doi:10.1088/0067-0049/211/1/10. S2CID 118847528.
Caballero-Nieves, S. M.; Nelan, E. P.; Gies, D. R.; Wallace, D. J.; DeGioia-Eastwood, K.; et al. (February 2014). "A High Angular Resolution Survey of Massive Stars in Cygnus OB2: Results from the Hubble Space Telescope Fine Guidance Sensors". The Astronomical Journal. 147 (2). 40. arXiv:1311.5087. Bibcode:2014AJ....147...40C. doi:10.1088/0004-6256/147/2/40. S2CID 22036552.
Prinja, R. K.; Massa, D. L. (October 2010). "Signature of wide-spread clumping in B supergiant winds". Astronomy and Astrophysics. 521. L55. arXiv:1007.2744. Bibcode:2010A&A...521L..55P. doi:10.1051/0004-6361/201015252. S2CID 59151633.
Nazé, Y. (November 2009). "Hot stars observed by XMM-Newton. I. The catalog and the properties of OB stars". Astronomy and Astrophysics. 506 (2): 1055–1064. arXiv:0908.1461. Bibcode:2009A&A...506.1055N. doi:10.1051/0004-6361/200912659. S2CID 17317459.
Lyubimkov, Leonid S.; Lambert, David L.; Rostopchin, Sergey I.; Rachkovskaya, Tamara M.; Poklad, Dmitry B. (February 2010). "Accurate fundamental parameters for A-, F- and G-type Supergiants in the solar neighbourhood". Monthly Notices of the Royal Astronomical Society. 402 (2): 1369–1379. arXiv:0911.1335. Bibcode:2010MNRAS.402.1369L. doi:10.1111/j.1365-2966.2009.15979.x. S2CID 119096173.
Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Robinson, P. E. (October 2003). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I". The Astronomical Journal. 126 (4): 2048–2059. arXiv:astro-ph/0308182. Bibcode:2003AJ....126.2048G. doi:10.1086/378365. S2CID 119417105.
Shenavrin, V. I.; Taranova, O. G.; Nadzhip, A. E. (January 2011). "Search for and study of hot circumstellar dust envelopes". Astronomy Reports. 55 (1): 31–81. Bibcode:2011ARep...55...31S. doi:10.1134/S1063772911010070. S2CID 122700080.
Cenarro, A. J.; Peletier, R. F.; Sanchez-Blazquez, P.; Selam, S. O.; Toloba, E.; Cardiel, N.; Falcon-Barroso, J.; Gorgas, J.; Jimenez-Vicente, J.; Vazdekis, A. (January 2007). "Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar atmospheric parameters". Monthly Notices of the Royal Astronomical Society. 374 (2): 664–690. arXiv:astro-ph/0611618. Bibcode:2007MNRAS.374..664C. doi:10.1111/j.1365-2966.2006.11196.x. S2CID 119428437.
Sion, Edward M.; Holberg, J. B.; Oswalt, Terry D.; McCook, George P.; Wasatonic, Richard (December 2009). "The White Dwarfs Within 20 Parsecs of the Sun: Kinematics and Statistics". The Astronomical Journal. 138 (6): 1681–1689. arXiv:0910.1288. Bibcode:2009AJ....138.1681S. doi:10.1088/0004-6256/138/6/1681. S2CID 119284418.
Arias, Julia I.; et al. (August 2016). "Spectral Classification and Properties of the OVz Stars in the Galactic O Star Spectroscopic Survey (GOSSS)". The Astronomical Journal. 152 (2): 31. arXiv:1604.03842. Bibcode:2016AJ....152...31A. doi:10.3847/0004-6256/152/2/31. S2CID 119259952.
Maíz Apellániz, J.; Walborn, Nolan R.; Morrell, N. I.; Niemela, V. S.; Nelan, E. P. (2007). "Pismis 24-1: The Stellar Upper Mass Limit Preserved". The Astrophysical Journal. 660 (2): 1480–1485. arXiv:astro-ph/0612012. Bibcode:2007ApJ...660.1480M. doi:10.1086/513098. S2CID 15936535.
Walborn, Nolan R.; Sota, Alfredo; Maíz Apellániz, Jesús; Alfaro, Emilio J.; Morrell, Nidia I.; Barbá, Rodolfo H.; Arias, Julia I.; Gamen, Roberto C. (2010). "Early Results from the Galactic O-Star Spectroscopic Survey: C III Emission Lines in of Spectra". The Astrophysical Journal Letters. 711 (2): L143. arXiv:1002.3293. Bibcode:2010ApJ...711L.143W. doi:10.1088/2041-8205/711/2/L143. S2CID 119122481.
Fariña, Cecilia; Bosch, Guillermo L.; Morrell, Nidia I.; Barbá, Rodolfo H.; Walborn, Nolan R. (2009). "Spectroscopic Study of the N159/N160 Complex in the Large Magellanic Cloud". The Astronomical Journal. 138 (2): 510–516. arXiv:0907.1033. Bibcode:2009AJ....138..510F. doi:10.1088/0004-6256/138/2/510. S2CID 18844754.
Rauw, G.; Manfroid, J.; Gosset, E.; Nazé, Y.; Sana, H.; De Becker, M.; Foellmi, C.; Moffat, A. F. J. (2007). "Early-type stars in the core of the young open cluster Westerlund 2". Astronomy and Astrophysics. 463 (3): 981–991. arXiv:astro-ph/0612622. Bibcode:2007A&A...463..981R. doi:10.1051/0004-6361:20066495. S2CID 17776145.
Crowther, Paul A. (2007). "Physical Properties of Wolf-Rayet Stars". Annual Review of Astronomy & Astrophysics. 45 (1): 177–219. arXiv:astro-ph/0610356. Bibcode:2007ARA&A..45..177C. doi:10.1146/annurev.astro.45.051806.110615. S2CID 1076292.
Norris, Jackson M.; Wright, Jason T.; Wade, Richard A.; Mahadevan, Suvrath; Gettel, Sara (December 2011). "Non-detection of the Putative Substellar Companion to HD 149382". The Astrophysical Journal. 743 (1). 88. arXiv:1110.1384. Bibcode:2011ApJ...743...88N. doi:10.1088/0004-637X/743/1/88. S2CID 118337277.
Walborn, Nolan R.; Howarth, Ian D.; Lennon, Daniel J.; Massey, Philip; Oey, M. S.; Moffat, Anthony F. J.; Skalkowski, Gwen; Morrell, Nidia I.; Drissen, Laurent; Parker, Joel Wm. (2002). "A New Spectral Classification System for the Earliest O Stars: Definition of Type O2" (PDF). The Astronomical Journal. 123 (5): 2754–2771. Bibcode:2002AJ....123.2754W. doi:10.1086/339831. S2CID 122127697.
Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373. S2CID 123149047.
Miszalski, B.; Crowther, P. A.; De Marco, O.; Köppen, J.; Moffat, A. F. J.; Acker, A.; Hillwig, T. C. (2012). "IC 4663: The first unambiguous [WN] Wolf-Rayet central star of a planetary nebula". Monthly Notices of the Royal Astronomical Society. 423 (1): 934–947. arXiv:1203.3303. Bibcode:2012MNRAS.423..934M. doi:10.1111/j.1365-2966.2012.20929.x. S2CID 10264296.
Crowther, P. A.; Walborn, N. R. (2011). "Spectral classification of O2-3.5 If*/WN5-7 stars". Monthly Notices of the Royal Astronomical Society. 416 (2): 1311–1323. arXiv:1105.4757. Bibcode:2011MNRAS.416.1311C. doi:10.1111/j.1365-2966.2011.19129.x. S2CID 118455138.
Kirkpatrick, J. Davy (2005). "New Spectral Types L and T" (PDF). Annual Review of Astronomy and Astrophysics. 43 (1): 195–246. Bibcode:2005ARA&A..43..195K. doi:10.1146/annurev.astro.42.053102.134017. S2CID 122318616.
Kirkpatrick, J. Davy; Barman, Travis S.; Burgasser, Adam J.; McGovern, Mark R.; McLean, Ian S.; Tinney, Christopher G.; Lowrance, Patrick J. (2006). "Discovery of a Very Young Field L Dwarf, 2MASS J01415823−4633574". The Astrophysical Journal. 639 (2): 1120–1128. arXiv:astro-ph/0511462. Bibcode:2006ApJ...639.1120K. doi:10.1086/499622. S2CID 13075577.
Kirkpatrick, J. Davy; Cushing, Michael C.; Gelino, Christopher R.; Beichman, Charles A.; Tinney, C. G.; Faherty, Jacqueline K.; Schneider, Adam; Mace, Gregory N. (2013). "Discovery of the Y1 Dwarf WISE J064723.23-623235.5". The Astrophysical Journal. 776 (2): 128. arXiv:1308.5372. Bibcode:2013ApJ...776..128K. doi:10.1088/0004-637X/776/2/128. S2CID 6230841.
Deacon, N. R.; Hambly, N. C. (2006). "Y-Spectral class for Ultra-Cool Dwarfs". Monthly Notices of the Royal Astronomical Society. 371: 1722–1730. arXiv:astro-ph/0607305. doi:10.1111/j.1365-2966.2006.10795.x. S2CID 14081778.
Zuckerman, B.; Song, I. (2009). "The minimum Jeans mass, brown dwarf companion IMF, and predictions for detection of Y-type dwarfs". Astronomy and Astrophysics. 493 (3): 1149–1154. arXiv:0811.0429. Bibcode:2009A&A...493.1149Z. doi:10.1051/0004-6361:200810038. S2CID 18147550.
Dupuy, T. J.; Kraus, A. L. (2013). "Distances, Luminosities, and Temperatures of the Coldest Known Substellar Objects". Science. 341 (6153): 1492–5. arXiv:1309.1422. Bibcode:2013Sci...341.1492D. doi:10.1126/science.1241917. PMID 24009359. S2CID 30379513.
Leggett, Sandy K.; Cushing, Michael C.; Saumon, Didier; Marley, Mark S.; Roellig, Thomas L.; Warren, Stephen J.; Burningham, Ben; Jones, Hugh R. A.; Kirkpatrick, J. Davy; Lodieu, Nicolas; Lucas, Philip W.; Mainzer, Amy K.; Martín, Eduardo L.; McCaughrean, Mark J.; Pinfield, David J.; Sloan, Gregory C.; Smart, Richard L.; Tamura, Motohide; Van Cleve, Jeffrey E. (2009). "The Physical Properties of Four ~600 K T Dwarfs". The Astrophysical Journal. 695 (2): 1517–1526. arXiv:0901.4093. Bibcode:2009ApJ...695.1517L. doi:10.1088/0004-637X/695/2/1517. S2CID 44050900.
Delorme, Philippe; Delfosse, Xavier; Albert, Loïc; Artigau, Étienne; Forveille, Thierry; Reylé, Céline; Allard, France; Homeier, Derek; Robin, Annie C.; Willott, Chris J.; Liu, Michael C.; Dupuy, Trent J. (2008). "CFBDS J005910.90-011401.3: Reaching the T-Y brown dwarf transition?". Astronomy and Astrophysics. 482 (3): 961–971. arXiv:0802.4387. Bibcode:2008A&A...482..961D. doi:10.1051/0004-6361:20079317. S2CID 847552.
Burningham, Ben; Pinfield, D. J.; Leggett, S. K.; Tamura, M.; Lucas, P. W.; Homeier, D.; Day-Jones, A.; Jones, H. R. A.; Clarke, J. R. A.; Ishii, M.; Kuzuhara, M.; Lodieu, N.; Zapatero-Osorio, María Rosa; Venemans, B. P.; Mortlock, D. J.; Barrado y Navascués, D.; Martin, Eduardo L.; Magazzù, Antonio (2008). "Exploring the substellar temperature regime down to ~550 K". Monthly Notices of the Royal Astronomical Society. 391 (1): 320–333. arXiv:0806.0067. Bibcode:2008MNRAS.391..320B. doi:10.1111/j.1365-2966.2008.13885.x. S2CID 1438322.
Luhman, Kevin L.; Esplin, Taran L. (May 2016). "The Spectral Energy Distribution of the Coldest Known Brown Dwarf". The Astronomical Journal. 152 (3): 78. arXiv:1605.06655. Bibcode:2016AJ....152...78L. doi:10.3847/0004-6256/152/3/78. S2CID 118577918.
Burningham, Ben; Smith, L.; Cardoso, C.V.; Lucas, P.W.; Burgasser, Adam J.; Jones, H.R.A.; Smart, R.L. (May 2014). "The discovery of a T6.5 subdwarf". Monthly Notices of the Royal Astronomical Society. 440 (1): 359–364. arXiv:1401.5982. Bibcode:2014MNRAS.440..359B. doi:10.1093/mnras/stu184. ISSN 0035-8711. S2CID 119283917.
Cruz, Kelle L.; Kirkpatrick, J. Davy; Burgasser, Adam J. (February 2009). "Young L dwarfs identified in the field: A preliminary low-gravity, optical spectral Sequence from L0 to L5". The Astronomical Journal. 137 (2): 3345–3357. arXiv:0812.0364. Bibcode:2009AJ....137.3345C. doi:10.1088/0004-6256/137/2/3345. ISSN 0004-6256. S2CID 15376964.
Looper, Dagny L.; Kirkpatrick, J. Davy; Cutri, Roc M.; Barman, Travis; Burgasser, Adam J.; Cushing, Michael C.; Roellig, Thomas; McGovern, Mark R.; McLean, Ian S.; Rice, Emily; Swift, Brandon J. (October 2008). "Discovery of two nearby peculiar L dwarfs from the 2MASS Proper-Motion Survey: Young or metal-rich?". Astrophysical Journal. 686 (1): 528–541. arXiv:0806.1059. Bibcode:2008ApJ...686..528L. doi:10.1086/591025. ISSN 0004-637X. S2CID 18381182.
Kirkpatrick, J. Davy; Looper, Dagny L.; Burgasser, Adam J.; Schurr, Steven D.; Cutri, Roc M.; Cushing, Michael C.; Cruz, Kelle L.; Sweet, Anne C.; Knapp, Gillian R.; Barman, Travis S.; Bochanski, John J. (September 2010). "Discoveries from a near-infrared proper motion survey using multi-epoch Two Micron All-Sky Survey data". Astrophysical Journal Supplement Series. 190 (1): 100–146. arXiv:1008.3591. Bibcode:2010ApJS..190..100K. doi:10.1088/0067-0049/190/1/100. ISSN 0067-0049. S2CID 118435904.
Faherty, Jacqueline K.; Riedel, Adric R.; Cruz, Kelle L.; Gagne, Jonathan; Filippazzo, Joseph C.; Lambrides, Erini; Fica, Haley; Weinberger, Alycia; Thorstensen, John R.; Tinney, C.G.; Baldassare, Vivienne (July 2016). "Population properties of brown dwarf analogs to exoplanets". Astrophysical Journal Supplement Series. 225 (1): 10. arXiv:1605.07927. Bibcode:2016ApJS..225...10F. doi:10.3847/0067-0049/225/1/10. ISSN 0067-0049. S2CID 118446190.
Córsico, A. H.; Althaus, L. G. (2004). "The rate of period change in pulsating DB-white dwarf stars". Astronomy and Astrophysics. 428: 159–170. arXiv:astro-ph/0408237. Bibcode:2004A&A...428..159C. doi:10.1051/0004-6361:20041372. S2CID 14653913.
McCook, George P.; Sion, Edward M. (1999). "A Catalog of Spectroscopically Identified White Dwarfs". The Astrophysical Journal Supplement Series. 121 (1): 1–130. Bibcode:1999ApJS..121....1M. CiteSeerX 10.1.1.565.5507. doi:10.1086/313186. S2CID 122286998.
Yakovlev, D. G.; Kaminker, A. D.; Haensel, P.; Gnedin, O. Y. (2002). "The cooling neutron star in 3C 58". Astronomy & Astrophysics. 389: L24 – L27. arXiv:astro-ph/0204233. Bibcode:2002A&A...389L..24Y. doi:10.1051/0004-6361:20020699. S2CID 6247160.

skyandtelescope.com (Global: 8,316^th place; English: 7,545^th place)

MacRobert, Alan (1 August 2006). "The Spectral Types of Stars". Sky & Telescope.

solstation.com (Global: low place; English: low place)

"Stars within 20 light-years".
"Stars and Habitable Planets". www.solstation.com.

space.com (Global: 936^th place; English: 713^th place)

Elizabeth Howell (21 September 2013). "Regulus: The Kingly Star". Space.com. Retrieved 13 April 2022.

spacefellowship.com (Global: low place; English: low place)

"On a cosmological timescale, The Earth's period of habitability is nearly over | International Space Fellowship". Spacefellowship.com. Retrieved 22 May 2012.

spacetelescope.org (Global: 8,860^th place; English: 6,620^th place)

"Galactic refurbishment". www.spacetelescope.org. ESA/Hubble. Retrieved 29 April 2015.

stsci.edu (Global: low place; English: low place)

"Colour-magnitude data". Space Telescope Science Institute (www.stsci.edu). Retrieved 6 March 2020.

sunysb.edu (Global: 9,785^th place; English: 9,347^th place)

astro.sunysb.edu

"AST 101: The Great Mnemonic Contest". Retrieved 10 June 2025.

swin.edu.au (Global: low place; English: low place)

astronomy.swin.edu.au

"Morgan-Keenan Luminosity Class | COSMOS". astronomy.swin.edu.au. Retrieved 31 August 2022.

u-strasbg.fr (Global: 1,342^nd place; English: 1,819^th place)

simbad.u-strasbg.fr

"Spectral type codes". simbad.u-strasbg.fr. Retrieved 6 March 2020.

ucl.ac.uk (Global: 1,306^th place; English: 885^th place)

star.ucl.ac.uk

"Mnemonics for the Harvard Spectral Classification Scheme". Retrieved 10 June 2025.
Allen, J. S. "The Classification of Stellar Spectra". UCL Department of Physics and Astronomy: Astrophysics Group. Retrieved 1 January 2014.

ucl.ac.uk

UCL (30 November 2018). "The MKK and Revised MK Atlas". UCL Observatory (UCLO). Retrieved 31 August 2022.

discovery.ucl.ac.uk

Walborn, Nolan R.; Howarth, Ian D.; Lennon, Daniel J.; Massey, Philip; Oey, M. S.; Moffat, Anthony F. J.; Skalkowski, Gwen; Morrell, Nidia I.; Drissen, Laurent; Parker, Joel Wm. (2002). "A New Spectral Classification System for the Earliest O Stars: Definition of Type O2" (PDF). The Astronomical Journal. 123 (5): 2754–2771. Bibcode:2002AJ....123.2754W. doi:10.1086/339831. S2CID 122127697.

ufl.edu (Global: 921^st place; English: 644^th place)

astro.ufl.edu

"Classification of Stellar Spectra: Some History".

uni-heidelberg.de (Global: 1,681^st place; English: 2,023^rd place)

lsw.uni-heidelberg.de

Camenzind, Max (27 September 2006). "Classification of Stellar Spectra and its Physical Interpretation" (PDF). Astro Lab Landessternwarte Königstuhl: 6 – via Heidelberg University.

vendian.org (Global: low place; English: low place)

Charity, Mitchell. "What color are the stars?". Vendian.org. Retrieved 13 May 2006.

web.archive.org (Global: 1^st place; English: 1^st place)

O'Connell (27 March 2023). "MAGNITUDE AND COLOR SYSTEMS" (PDF). Caltech ASTR 511. Archived (PDF) from the original on 28 March 2023. Retrieved 27 March 2023.
"The Colour of Stars". Australia Telescope Outreach and Education. 21 December 2004. Archived from the original on 3 December 2013. Retrieved 26 September 2007. — Explains the reason for the difference in color perception.
"Discovered: Stars as Cool as the Human Body | Science Mission Directorate". science.nasa.gov. Archived from the original on 7 October 2011. Retrieved 12 July 2017.
"NASA - NASA'S Wise Mission Discovers Coolest Class of Stars". www.nasa.gov. Archived from the original on 14 February 2021. Retrieved 1 November 2019.

wired.com (Global: 193^rd place; English: 152^nd place)

Venton, Danielle (23 August 2011). "NASA Satellite Finds Coldest, Darkest Stars Yet". Wired – via www.wired.com.

worldcat.org (Global: 5^th place; English: 5^th place)

search.worldcat.org

Morgan, William Wilson; Keenan, Philip Childs; Kellman, Edith (1943). An atlas of stellar spectra, with an outline of spectral classification. The University of Chicago Press. Bibcode:1943assw.book.....M. OCLC 1806249.
"Antonia Maury". www.projectcontinua.org. Retrieved 10 June 2020.
Hearnshaw, J.B. (17 March 2014). The analysis of starlight: Two centuries of astronomical spectroscopy (2nd ed.). New York, NY. ISBN 978-1-107-03174-6. OCLC 855909920.{{cite book}}: CS1 maint: location missing publisher (link)
Gray, Richard O.; Corbally, Christopher J.; Burgasser, Adam J. (2009). Stellar spectral classification. Princeton, NJ: Princeton University Press. ISBN 978-0-691-12510-7. OCLC 276340686.
Jones, Bessie Zaban; Boyd, Lyle Gifford (1971). The Harvard College Observatory: The first four directorships, 1839-1919 (1st ed.). Cambridge: M.A. Belknap Press of Harvard University Press. ISBN 978-0-674-41880-6. OCLC 1013948519.
Garrison, R. F. (1994). "A Hierarchy of Standards for the MK Process" (PDF). In Corbally, C. J.; Gray, R. O.; Garrison, R. F. (eds.). The MK Process at 50 Years: A Powerful Tool for Astrophysical Insight. Astronomical Society of the Pacific conference series. Vol. 60. San Francisco: Astronomical Society of the Pacific. pp. 3–14. ISBN 978-1-58381-396-6. OCLC 680222523.
Burningham, Ben; Smith, L.; Cardoso, C.V.; Lucas, P.W.; Burgasser, Adam J.; Jones, H.R.A.; Smart, R.L. (May 2014). "The discovery of a T6.5 subdwarf". Monthly Notices of the Royal Astronomical Society. 440 (1): 359–364. arXiv:1401.5982. Bibcode:2014MNRAS.440..359B. doi:10.1093/mnras/stu184. ISSN 0035-8711. S2CID 119283917.
Cruz, Kelle L.; Kirkpatrick, J. Davy; Burgasser, Adam J. (February 2009). "Young L dwarfs identified in the field: A preliminary low-gravity, optical spectral Sequence from L0 to L5". The Astronomical Journal. 137 (2): 3345–3357. arXiv:0812.0364. Bibcode:2009AJ....137.3345C. doi:10.1088/0004-6256/137/2/3345. ISSN 0004-6256. S2CID 15376964.
Looper, Dagny L.; Kirkpatrick, J. Davy; Cutri, Roc M.; Barman, Travis; Burgasser, Adam J.; Cushing, Michael C.; Roellig, Thomas; McGovern, Mark R.; McLean, Ian S.; Rice, Emily; Swift, Brandon J. (October 2008). "Discovery of two nearby peculiar L dwarfs from the 2MASS Proper-Motion Survey: Young or metal-rich?". Astrophysical Journal. 686 (1): 528–541. arXiv:0806.1059. Bibcode:2008ApJ...686..528L. doi:10.1086/591025. ISSN 0004-637X. S2CID 18381182.
Kirkpatrick, J. Davy; Looper, Dagny L.; Burgasser, Adam J.; Schurr, Steven D.; Cutri, Roc M.; Cushing, Michael C.; Cruz, Kelle L.; Sweet, Anne C.; Knapp, Gillian R.; Barman, Travis S.; Bochanski, John J. (September 2010). "Discoveries from a near-infrared proper motion survey using multi-epoch Two Micron All-Sky Survey data". Astrophysical Journal Supplement Series. 190 (1): 100–146. arXiv:1008.3591. Bibcode:2010ApJS..190..100K. doi:10.1088/0067-0049/190/1/100. ISSN 0067-0049. S2CID 118435904.
Faherty, Jacqueline K.; Riedel, Adric R.; Cruz, Kelle L.; Gagne, Jonathan; Filippazzo, Joseph C.; Lambrides, Erini; Fica, Haley; Weinberger, Alycia; Thorstensen, John R.; Tinney, C.G.; Baldassare, Vivienne (July 2016). "Population properties of brown dwarf analogs to exoplanets". Astrophysical Journal Supplement Series. 225 (1): 10. arXiv:1605.07927. Bibcode:2016ApJS..225...10F. doi:10.3847/0067-0049/225/1/10. ISSN 0067-0049. S2CID 118446190.
Apellániz, J. Maíz; Barbá, R. H.; Aranda, R. Fernández; González, M. Pantaleoni; Bellido, P. Crespo; Sota, A.; Alfaro, E. J. (1 January 2022). "The Villafranca catalog of Galactic OB groups – II. From Gaia DR2 to EDR3 and ten new systems with O stars". Astronomy & Astrophysics. 657: A131. arXiv:2110.01464. Bibcode:2022A&A...657A.131M. doi:10.1051/0004-6361/202142364. ISSN 0004-6361.
Massey, Philip; Neugent, Kathryn F.; Smart, Brianna M. (1 September 2016). "A spectroscopic survey of massive stars in M31 AND M33*". The Astronomical Journal. 152 (3): 62. arXiv:1604.00112. Bibcode:2016AJ....152...62M. doi:10.3847/0004-6256/152/3/62. ISSN 0004-6256.

yahoo.com (Global: 38^th place; English: 40^th place)

ca.news.yahoo.com

Wehner, Mike (24 August 2011). "NASA spots chilled-out stars cooler than the human body | Technology News Blog – Yahoo! News Canada". Ca.news.yahoo.com. Retrieved 22 May 2012.

Stellar classification (English Wikipedia)

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