A Satellite of the Andromeda Galaxy, M31
Rektascenzija | 00 : 40.4 (u:m) |
---|---|
Deklinacija | +41 : 41 (sto:m) |
Razdalja | 2900 (*1000 sv.l.) |
Vizual. magnituda | 8.5 (mag) |
Zorni kot | 17x10 (loc min) |
M110 is the second brighter satellite galaxy of the Andromeda galaxy M31, together with M32, and thus a member of the Local Group. Curiously, this galaxy was discovered by Charles Messier on August 10, 1773, and depicted on his fine drawing of the "Great Andromeda Nebula" and its companions published in 1807, but Messier did never himself include this object in his catalog, due to unknown reasons, perhaps a certain sloppiness in recording. It was the last additional object, added finally by Kenneth Glyn Jones in 1966. Independent of Messier's discovery, Caroline Herschel discovered M110 on August 27, 1783, little more than 10 years after Messier, and William Herschel numbered it H V.18.
The small elliptical galaxy M110 is at about the same distance as the Andromeda galaxy M31, about 2.9 million light years. It is of type E5 or E6 and is designated "peculiar" because it shows some unusual dark structure (probably dust clouds); it is now often classified as a dwarf spheroid galaxy, not a generic elliptical one (this would make it the first ever known dwarf spheroid, of course). Its mass was estimated to be between 3.6 and 15 billion solar masses. Apparently, despite its comparatively small size, this dwarf elliptical galaxy has also a remarkable system of 8 globular clusters in a halo around it.