In this drawing by Charles Messier, satellite galaxy M110 appears at the upper right.
Charles Messier never included the galaxy in his list, but it was depicted by him, together withM32, on his drawing of "Nébuleuse D'Andromède", later known as the Andromeda Galaxy. A label of the drawing indicates that Messier first saw the object in 1773.[a][10] M110 was independently discovered byCaroline Herschel on August 27, 1783; her brotherWilliam Herschel described her discovery in 1785.[b][10][11] The suggestion to assign the galaxy a Messier number was made by Kenneth Glyn Jones in 1967,[12] making it the last member of theMessier List.
This galaxy has amorphological classification of pec dE5, indicating a dwarf elliptical galaxy with aflattening of 50%. It is designated peculiar (pec) due to patches of dust and young blue stars near its center.[13] This is unusual for dwarf elliptical galaxies in general,[9] and the reason is unclear.[13] Unlike M32, M110 lacks evidence for asupermassive black hole at its center.[14]
The interstellar dust in M110 has a mass of(1.1–1.8)×104M☉ with a temperature of18–22 K, and the interstellar gas has(4–7)×106M☉. The inner region has sweeping deficiencies in itsinterstellar medium IM, most likely expelled bysupernova explosions. Tidal interactions with M31 may have stripped away a significant fraction of the expelled gas and dust, leaving the galaxy as a whole, as it presents, deficient in its IM density.[15]
Novae have been detected in this galaxy, including one discovered in 1999,[16] and another in 2002. The latter, designated EQ J004015.8+414420, had also been captured in images taken by theSloan Digital Sky Survey (SDSS) that October.[17]
The Andromeda Galaxy and its satellite galaxy, Messier 110, to the bottom-right of the center
About half of theAndromeda's satellite galaxies are orbiting it in a plane, with 14 out of 16 following the same sense of rotation. One theory proposes that these 16 once belonged to a subhalo surrounding M110, then the group was broken up bytidal forces during a close encounter with Andromeda.[18]
^Herschel, William (1785)."On the construction of the heavens".Philosophical Transactions of the Royal Society of London.75:213–266. From p. 262: "There is a very considerable, broad, pretty faint, small nebula near it [the Andromeda galaxy, M31]; my Sister [Caroline] discovered it August 27, 1783, with a Newtonian 2-feet sweeper. It shews the same faint colour with the great one, and is, no doubt, in the neighborhood of it. It is not [M32] … ; but this is about two-thirds of a degree north preceding it, in a line parallel to β [Beta] and ν [Nu] Andromedae."
^abFord, Holland C.; et al. (July 1973), "Planetary Nebulae in Local-Group Galaxies. I. Identifications in NGC 185, NGC 205, and NGC 221",Astrophysical Journal,183: L73,Bibcode:1973ApJ...183L..73F,doi:10.1086/181255
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