Sag DEG
Sag DEG is a small loop-shaped satellite galaxy of the Milky Way. It is known by other names, such as the Sagittarius dwarf elliptical galaxy or the Sagittarius dwarf spheroidal galaxy.
| Sag DEG [1] | |
|---|---|
| Observation data (J2000 epoch) | |
| Constellation | Sagittarius |
| Right ascension | 18h 55m 19.5s [2] |
| Declination | −30° 32′ 43″ [2] |
| Redshift | 140 ± ? km/s [2] |
| Distance | 65 ± 7 kly (20 ± 2 kpc) [3][4] |
| Apparent magnitude (V) | 4.5 [2] |
| Characteristics | |
| Type | dSph(t) [2] |
| Apparent size (V) | 450′.0 × 216′.0 [2] |
| Notable features | Heading for a collision with the Milky Way |
| Other designations | |
| Sagittarius dwarf elliptical galaxy,[5] Sgr dSph,[2] Sagittarius dwarf spheroidal,[2] Sgr I Dwarf [2] | |
It consists of four globular clusters. The main cluster having been discovered in 1994. Sag DEG is about 10,000 light-years in diameter, and is about 70,000 light-years from Earth.
It moves in a polar orbit (i.e. an orbit passing through the galactic plane) at a distance of about 50,000 light-years from the core of the Milky Way (about 1/3 the distance of the Large Magellanic Cloud). In its looping, spiralling path, it has passed through the plane of the Milky Way several times in the past.[6]
Sag DEG should not be confused with the Sagittarius dwarf irregular galaxy, or the Sag DIG, a small galaxy 3.4 million light-years distant.
References
change- ↑ "Name SDG". SIMBAD Astronomical Database. Retrieved 28 November 2006.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 "Saggitarius Dwarf Spheroidal". NASA/IPAC Extragalactic Database. Retrieved 28 November 2006.
- ↑ Karachentsev, I.D.; et al. (2004). "A catalog of neighboring galaxies". The Astronomical Journal. 127 (4): 2031–2068. Bibcode:2004AJ....127.2031K. doi:10.1086/382905. S2CID 124129428.
- ↑ Karachentsev, I.D.; Kashibadze, O.G (2006). "Masses of the local group and of the M81 group estimated from distortions in the local velocity field". Astrophysics. 49 (1): 3–18. Bibcode:2006Ap.....49....3K. doi:10.1007/s10511-006-0002-6. S2CID 120973010.
- ↑ Sagittarius Dwarf Elliptical Galaxy / Sag DEG
- ↑ "Star-crossed: Milky Way's spiral shape may result from a smaller galaxy's impact". Scientific American. 14 September 2011.