List of Andromeda's satellite galaxies
The Andromeda Galaxy (M31) has satellite galaxies just like the Milky Way. Orbiting M31 are at least 14 dwarf galaxies: the brightest and largest is M32, which can be seen with a backyard telescope. The second brightest and closest one to M32 is M110. The other galaxies are fainter, and were mostly discovered only starting from the 1970s.
On January 11, 2006, it was announced that Andromeda's faint companion galaxies lie on or close to a single plane running through Andromeda's center. This unexpected distribution is not obviously understood in the context of current models for galaxy formation. The plane of satellite galaxies points toward a nearby group of galaxies (M81 Group), possibly tracing the large-scale distribution of dark matter.
Contents
Table of known satellites
Andromeda Galaxy's satellites are listed here by discovery (orbital distance is not known).
| Name | Type | Distance from Sun (million ly) |
Absolute Magnitude[1] | Magnitude | Mass-to-light ratio | Year discovered |
Notes |
|---|---|---|---|---|---|---|---|
| M32 | dE2 | 2.48 | +9.2 | 1749 | |||
| M110 | dE6 | 2.69 | +9.4 | 1773 | |||
| NGC 185 | dE5 | 2.01 | +11 | 1787 | |||
| NGC 147 | dE5 | 2.2 | +12 | 1829 | |||
| Andromeda I | dSph | 2.43 | -11.8 | +13.2 | 31 ± 6 [1] | 1970 | |
| Andromeda II | dSph | 2.13 | -12.6 | +13 | 13 ± 3 [1] | 1970 | |
| Andromeda III | dSph | 2.44 | -10.2 | +10.3 | 19 ± 12 [1] | 1970 | |
| Andromeda IV * | dIm? | 1972 | |||||
| Andromeda V | dSph | 2.52 | -9.6 | +15.4 | 78 ± 50 [2] | 1998 | |
| Pegasus Dwarf Spheroidal (Andromeda VI) |
dSph | 2.55 | -11.5 | +14.5 | 12 ± 5 [2] | 1998 | |
| Cassiopeia Dwarf (Andromeda VII) |
dSph | 2.49 | -13.3 | 7.1 ± 2.8 [1] | 1998 | ||
| Andromeda VIII | dSph | 2.7 | +9.1 | 2003 | |||
| Andromeda IX | dSph | 2.5 | -8.3 | +16.2 | 2004 | ||
| Andromeda X | dSph | 2.9 | -8.1 | +16.2 | 63 ± 40 [1] | 2005 | |
| Andromeda XI[3] | dSph | -7.3 | 2006 | ||||
| Andromeda XII[3] | dSph | -6.4 | 2006 | ||||
| Andromeda XIII[3] | dSph | -6.9 | 2006 | ||||
| Andromeda XIV[4] | dSph | -8.3 | 102 ± 71 [1] | 2007 | |||
| Andromeda XV[4] | dSph | -9.4 | 2007 | ||||
| Andromeda XVI[4] | dSph | -9.2 | 2007 | ||||
| Andromeda XVII[4] | dSph | -8.5 | 2008 | ||||
| Andromeda XVIII[4] | 2008 | ||||||
| Andromeda XIX[4] | dSph | -9.3 | 2008 | ||||
| Andromeda XX[4] | dSph | -6.3 | 2008 | ||||
| Andromeda XXI[4] | dSph | -9.9 | 2009 | ||||
| Andromeda XXII[4] | dSph | -7.0 | 2009 | ||||
| Andromeda XXIII[4] | 2011 | ||||||
| Andromeda XXIV[4] | 2011 | ||||||
| Andromeda XXV[4] | 2011 | ||||||
| Andromeda XXVI[4] | 2011 | ||||||
| Andromeda XXVII[4] | 2011 | ||||||
| Andromeda XXVIII[5] | 2011 | ||||||
| Andromeda XXIX[5] | 2011 | ||||||
| Tidal Stream Northwest (Tidal Stream E and F)[6] |
2009 | ||||||
| Tidal Stream Southwest[6] | 2009 | ||||||
| Triangulum Galaxy* (M33) |
SA(s)cd | 2.59 | +6.27 | 1654? |
* It is uncertain whether is a companion galaxy of the Andromeda Galaxy.
Interacting with Andromeda
New images from NASA's Spitzer Space Telescope shed light on the Andromeda Galaxy's violent past. The images show that one of Andromeda's satellite galaxies, M32, blasted through one of Andromeda's spiral arms a few million years ago. Infrared pictures of Andromeda's two spiral arms demonstrate that they and the prominent star-forming ring are separate structures. The images also show a hole where the rings seem to split into arcs. This hole is where astronomers believe M32 punched through Andromeda's galactic disk.
See also
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 The SPLASH Survey: Internal Kinematics, Chemical Abundances, and Masses of the Andromeda I, II, III, VII, X, and XIV Dwarf Spheroidal Galaxies, Kalirai, J. S. et al., 2010
- ↑ 2.0 2.1 The scatter about the 'Universal' dwarf spheroidal mass profile: a kinematic study of the M31 satellites And V and And VI, Collins, M.L.M. et al., 2011.
- ↑ 3.0 3.1 3.2 Discovery and analysis of three faint dwarf galaxies and a globular cluster in the outer halo of the Andromeda galaxy, N. F. Martin et.al, 2006.
- ↑ 4.00 4.01 4.02 4.03 4.04 4.05 4.06 4.07 4.08 4.09 4.10 4.11 4.12 4.13 Discovery of the Local Group Galaxies
- ↑ 5.0 5.1 Lua error in package.lua at line 80: module 'strict' not found. (reprinted in R&D Magazine)
- ↑ 6.0 6.1 New tidal streams found in Andromeda reveal history of galactic mergers
External links
- Andromeda's thin sheet of satellites - Dark matter filiments or galaxtic cannibalism?
- Strange Setup: Andromeda's Satellite Galaxies All Lined Up
| Location |
Andromeda Galaxy→Andromeda subgroup → Local Group → Virgo Supercluster → Laniakea Supercluster → Observable universe → Universe
Each → may be read as "within" or "part of". |
.jpg) |
|---|---|---|
| Satellite galaxies |
*It is uncertain whether the Triangulum Galaxy is a companion galaxy of the Andromeda Galaxy |
|
| Other | ||
