Beta Octantis
Astrometric binary star in the constellation Octans From Wikipedia, the free encyclopedia
Beta Octantis, Latinized from β Octantis, is a probable astrometric binary[10] star system in the southern circumpolar constellation of Octans. It is faintly visible to the naked eye with an apparent visual magnitude of 4.13.[2] Based upon an annual parallax shift of 21.85 mas as seen from Earth, it is located about 149 light years from the Sun. It is moving away from the Sun with a radial velocity of +19 km/s.[5]
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Octans |
| Right ascension | 22h 46m 03.51098s[1] |
| Declination | −81° 22′ 53.8120″[1] |
| Apparent magnitude (V) | 4.13[2] |
| Characteristics | |
| Spectral type | A9IV-V[3] |
| U−B color index | +0.11[4] |
| B−V color index | +0.20[4] |
| Astrometry | |
| Radial velocity (Rv) | +19.0±0.6[5] km/s |
| Proper motion (μ) | RA: −54.49[1] mas/yr Dec.: +1.16[1] mas/yr |
| Parallax (π) | 21.85 ± 0.43 mas[1] |
| Distance | 149 ± 3 ly (45.8 ± 0.9 pc) |
| Absolute magnitude (MV) | +0.83[2] |
| Details | |
| Mass | 2.27[6] M☉ |
| Radius | 3.2[7] R☉ |
| Luminosity | 42[6] L☉ |
| Surface gravity (log g) | 4.15[8] cgs |
| Temperature | 8,006[8] K |
| Metallicity [Fe/H] | −0.02[9] dex |
| Rotational velocity (v sin i) | 49[6] km/s |
| Age | 496[8] Myr |
| Other designations | |
| Database references | |
| SIMBAD | data |
Based upon a stellar classification of A9IV-V,[3] the visible component is an evolving, white-hued A-type star with a spectrum that shows mixed traits of a main sequence and a subgiant star. It has an estimated 2.27[6] times the mass of the Sun and 3.2[7] times the Sun's radius. The star is around 500 million years old[8] with a projected rotational velocity of 49 km/s.[6] It is radiating 42[6] times the Sun's luminosity from its photosphere at an effective temperature of 8,006 K.[8]
References
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