Analysis of information sources in references of the Wikipedia article "90377 เซดนา" in Thai language version.
Objects with distance from Sun over 59 AU
the census of dwarf planet satellites shows all the biggest systems seem to have satellites. Sedna isn't known to, but any satellite would spend at least a quarter of its time lost in Sedna's glare [...] no additional satellites for Makemake, Eris and OR10 down to 26th mag. Haumea has already been checked. Sedna the last remaining to double-check!