Sextans B
| Sextans B | |
|---|---|
 |
|
| Observation data (J2000 epoch) | |
| Constellation | Sextans |
| Right ascension | 10h 00m 00.1s[1] |
| Declination | +05° 19′ 56″[1] |
| Redshift | 300 ± 0 km/s[1] |
| Distance | 4.44 ± 0.23 Mly (1.36 ± 0.07 Mpc)[2][3] |
| Type | ImIV-V[1] |
| Apparent dimensions (V) | 5′.1 × 3′.5[1] |
| Apparent magnitude (V) | 11.9[1] |
| Other designations | |
| UGC 5373,[1] PGC 28913,[1] DDO 70,[1] Sex B[1] | |
Sextans B (also known as UGC 5373 and DDO 70) is an irregular galaxy that may be part of the Local Group, or lie just beyond it. Sextans B is 4.44 million light-years away from Earth and thus is one of most distant members of the Local Group, if it is indeed a member. It forms a pair with its neighbouring galaxy Sextans A.[4] It is a type Ir IV-V galaxy according to the galaxy morphological classification scheme.[5] Sextans B may also be gravitationally associated with the galaxies NGC 3109 and the Antlia Dwarf.[6]
Sextans B has a uniform stellar population,[7] but the interstellar medium in it may be inhomogeneous.[8] Its mass is estimated to be about 2 × 108 times the mass of the Sun, of which 5.5 × 107 is in the form of atomic hydrogen.[7] Star formation in the galaxy seems to have proceeded in distinct periods of low intensity, separated by shorter periods of no activity.[7] The existence of Cepheid variables in the galaxy implies that Sextans B contains at least some young stars.[5] The metallicity of Sextans B is rather low, with a value of approximately Z = 0.001.[7] Sextans B is receding from the Milky Way with a speed of approximately 300 kilometres per second (190 mi/s),[8] and probably lies just outside the edge of the Local Group, so as its neighbour Sextans A.[9]
Five planetary nebulae have been identified in Sextans B. It is one of the smallest galaxies in which planetary nebulae have been observed. These appear point-like and can be identified by their spectral emission lines.[10] It also contains a massive globular cluster.[11]
References
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- Sextans B on WikiSky: DSS2, SDSS, GALEX, IRAS, Hydrogen α, X-Ray, Astrophoto, Sky Map, Articles and images
Coordinates: 
10h 00m 00.1s, +05° 19′ 56″
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