Epsilon Octantis
  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Octans |
| Right ascension | 22h 20m 01.67970s[1] |
| Declination | −80° 26′ 23.0947″[1] |
| Apparent magnitude (V) | 4.58 - 5.30[2] |
| Characteristics | |
| Spectral type | M5III[3] |
| U−B color index | +1.18[4] |
| B−V color index | +1.47[4] |
| Variable type | SRb[2] |
| Astrometry | |
| Radial velocity (Rv) | +11.70[5] km/s |
| Proper motion (μ) | RA: +56.81[1] mas/yr Dec.: −43.47[1] mas/yr |
| Parallax (π) | 11.22±0.23 mas[1] |
| Distance | 291 ± 6 ly (89 ± 2 pc) |
| Absolute magnitude (MV) | +0.34[6] |
| Details | |
| Mass | 1.34[7] M☉ |
| Radius | 112±15[8] R☉ |
| Luminosity | 1,819[8] L☉ |
| Surface gravity (log g) | 2.15[7] cgs |
| Temperature | 3,560±264[8] K |
| Other designations | |
| BO Oct, ε Oct, CD−81°831, FK5 839, GC 31166, HD 210967, HIP 110256, HR 8481, SAO 258928 | |
| Database references | |
| SIMBAD | data |
Epsilon Octantis, Latinized from ε Octantis, is a star in the southern circumpolar constellation of Octans. It is a faintly visible to the naked eye with an apparent visual magnitude of about 5. The annual parallax shift of 11.22[1] mas yields a distance estimate of around 291 light years. It is moving further from the Sun with a radial velocity of +11.7 km/s.[5]
This is an evolved, cool red giant star with a stellar classification of class M5III.[3] It is a semiregular variable with a magnitude range of 4.58 to 5.30 and a (poorly defined) period around 55 days.[2] The star has 1.34[7] times the mass of the Sun and has expanded to around 112[8] times the Sun's radius. It is radiating 1,819[8] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 3,560 K.[8]
Epsilon Octantis was found to be variable on a survey of the southern sky conducted by the Bamberg observatory, which was reported in 1966.[10] In 1972, it was assigned the variable star designation BO Octantis,[11] although this is now recognised as a mistake since stars with Bayer designations are not given a separate variable star designation.[2]
References
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- ^ a b c d Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).Vizier catalog entry
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Vizier catalog entry
- ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Vizier catalog entry
- ^ a b c d e f Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
