Using an assumed distance of 7.1 Megaparsec to Messier 108, based on a 1986 study.[1]
This is the angular size of the feature as it appears on the sky. The physical size depends on the distance to Messier 108, which is more difficult to measure. At the time of the study that discovered this feature (in 2003),[9] the accepted distance to Messier 108 was based on a 1988 work,[2] which gave a value of 14.1 Megaparsec (Mpc). This has been substantially revised down to 8.8 Mpc in a 2014 study.[3] At 14.1 Mpc, an angular size of 2.6 arcminutes would correspond to a physical size of kpc, or roughly 10 kiloparsec (kpc), which is the value given in the 2003 study. Using the more recent distance estimate, this would be kpc. Compare the list of distance measurements in the NASA/IPAC Extragalactic Database.[2]
Marsden, Brian G. (12 February 1969). "Circular No. 2131". Central Bureau for Astronomical Telegrams. Smithsonian Astrophysical Observatory. Retrieved 2 December 2024.
messier-objects.com
"Messier 108: Surfboard Galaxy". Messier Objects: Guide to the Bright Galaxies, Nebulae and Clusters Listed in the Messier Catalogue. 26 September 2015.