Beta Octantis

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]

β Octantis

Location of β Octantis (circled)
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
β Oct, CPD−82° 889, FK5 924, GC 31712, HD 214846, HIP 112405, HR 8630, SAO 258941
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]