Xi Octantis
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Octans |
| Right ascension | 22h 50m 22.8139s |
| Declination | −80° 07′ 25.842″ |
| Apparent magnitude (V) | 5.32 - 5.36 |
| Characteristics | |
| Evolutionary stage | main sequence |
| Spectral type | B6 V (B5/7 V) |
| U−B color index | −0.48 |
| B−V color index | −0.13 |
| Variable type | SPB |
| Astrometry | |
| Radial velocity (Rv) | 22.1±0.5 km/s |
| Proper motion (μ) | RA: +20.003 mas/yr Dec.: −12.607 mas/yr |
| Parallax (π) | 6.35±0.0644 mas |
| Distance | 514 ± 5 ly (157 ± 2 pc) |
| Absolute magnitude (MV) | −0.57 |
| Details | |
| Mass | 4.02±0.05 M☉ |
| Radius | 3.0±0.5 R☉ |
| Luminosity | 360+24 −22 L☉ |
| Surface gravity (log g) | 4.09 cgs |
| Temperature | 14,050 K |
| Metallicity [Fe/H] | −0.1 dex |
| Rotational velocity (v sin i) | 30 km/s |
| Age | 46+25 −16 Myr |
| Other designations | |
| ξ Oct, 77 G. Octantis, CD−80°828, CPD−80°1055, GC 31821, HD 215573, HIP 112781, HR 8663, SAO 258946 | |
| Database references | |
| SIMBAD | data |
Xi Octantis, Latinized from ξ Octantis, is a solitary variable star in the southern circumpolar constellation Octans. It has an apparent magnitude of about 5.3, allowing it to be faintly seen with the naked eye; however, this varies slightly. Located 514 light years away, the object is receding with a heliocentric radial velocity of 22 km/s.
Xi Octantis has a stellar classification of B6 V, indicating that it is an ordinary B-type main-sequence star. Hintler et al. gives it a luminosity class IV (subgiant) while Houk and Cowley gives a classification intermediate between a B5 and B7 dwarf. Nevertheless, it has 4 times the mass of the Sun and is 3 times larger. It shines with a luminosity of 360 L☉ from its photosphere at an effective temperature of 14,050 K, giving it a whitish blue glow. Xi Octantis is 46 million years old – 64.8% through its short main sequence lifetime – and spins modestly with a projected rotational velocity of 30 km/s.
When the Hipparcos catalogue was released in 1997, Xi Octantis was found to vary in magnitude — ranging from 5.32 to 5.36 based on data from the International Variable Star Index. It has since been classified as a Slowly pulsating B-dwarf with a period of 1.78 days.