Messier 110

Template:Short description Template:Infobox Galaxy

Messier 110, or M110, also known as NGC 205, is a dwarf elliptical galaxy that is a satellite of the Andromeda Galaxy in the Local Group.<ref name=carnegieatlas/>

Early observational historyEdit

File:M31 by Messier.jpg

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 with M32, 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.Template:Efn<ref name=jones1991/> M110 was independently discovered by Caroline Herschel on August 27, 1783; her brother William Herschel described her discovery in 1785.Template:Efn<ref name=jones1991/><ref>Template:Cite journal 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."</ref> The suggestion to assign the galaxy a Messier number was made by Kenneth Glyn Jones in 1967,<ref name=Jones1967/> making it the last member of the Messier List.

PropertiesEdit

This galaxy has a morphological classification of pec dE5, indicating a dwarf elliptical galaxy with a flattening of 50%. It is designated peculiar (pec) due to patches of dust and young blue stars near its center.<ref name=Ford1973/> This is unusual for dwarf elliptical galaxies in general,<ref name=carnegieatlas/> and the reason is unclear.<ref name=Ford1973/> Unlike M32, M110 lacks evidence for a supermassive black hole at its center.<ref name=Valluri2005/>

The interstellar dust in M110 has a mass of Template:Val with a temperature of Template:Val, and the interstellar gas has Template:Val. The inner region has sweeping deficiencies in its interstellar medium IM, most likely expelled by supernova 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.<ref name=DeLooze2012/>

Novae have been detected in this galaxy, including one discovered in 1999,<ref name=Bergh2000/> and another in 2002. The latter, designated EQ J004015.8+414420, had also been captured in images taken by the Sloan Digital Sky Survey (SDSS) that October.<ref name=astrofili/>

Local contextEdit

File:M31 09-01-2011.jpg

The Andromeda Galaxy and its satellite galaxy, Messier 110, to the bottom-right of the center

About half of the Andromeda'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 by tidal forces during a close encounter with Andromeda.<ref name=Angus2016/>