| Sextans A | |
|---|---|
 Irregular galaxy Sextans A. The bright Milky Way foreground stars appear yellowish in this view. Beyond them lie the stars of Sextans A with young blue star clusters clearly visible. | |
| Observation data (J2000epoch) | |
| Constellation | Sextans |
| Right ascension | 10h 11m 00.8s[1] |
| Declination | −04° 41′ 34″[1] |
| Redshift | 324 ± 2 km/s[1] |
| Distance | 4.31 ± 0.13Mly (1.32 ± 0.04Mpc)[2][3][4] |
| Apparent magnitude (V) | 11.9[1] |
| Characteristics | |
| Type | IBm[1] |
| Apparent size (V) | 5.9′ × 4.9′[1] |
| Notable features | Square in shape |
| Other designations | |
| UGCA 205,[1]DDO 75,[1]PGC 29653[1] | |
Sextans A (also known asUGCA 205) is a smalldwarfirregular galaxy. It spans about 5000 light-years across, and is located at 4.3 million light-years away, in the outskirts of theLocal Group of galaxies, which includes theMilky Way galaxy, and to which Sextans A may or may not belong.
Sextans A has a peculiar square shape. Massive short-lived stars exploded in supernovae that caused more star formation, triggering yet more supernovae, ultimately resulting in an expanding shell. Young blue stars now highlight areas and shell edges high in current star formation, which from the perspective of observers on Earth appears roughly square.[5] The 10.4 m telescopeGran Telescopio Canarias recently observed the OB-type stars that power the giant HII regions.[6]
Media related toSextans A at Wikimedia Commons