Eta Octantis

Eta Octantis, Latinized from η Octantis, is a solitary star located in the southern circumpolar constellation Octans. It has an apparent magnitude of 6.19,^[2] making it faintly visible to the naked eye. The object is situated at a distance of 358 light years^[1] but is approaching the Solar System with a heliocentric radial velocity of −1.7 km/s.^[6]

η Octantis

Location of η Octantis (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Octans
Right ascension	10h 59m 13.7578s[1]
Declination	−84° 35′ 38.0177″[1]
Apparent magnitude (V)	6.18±0.01[2]
Characteristics
Evolutionary stage	main sequence[3]
Spectral type	A1 Va[4]
U−B color index	+0.12[5]
B−V color index	+0.11[5]
Astrometry
Radial velocity (Rv)	−1.7±0.6[6] km/s
Proper motion (μ)	RA: −65.747 mas/yr[1] Dec.: −8.273 mas/yr[1]
Parallax (π)	9.1133±0.02 mas[1]
Distance	357.9 ± 0.8 ly (109.7 ± 0.2 pc)
Absolute magnitude (MV)	+1.08[7]
Details
Mass	2.37±0.03[3] M☉
Radius	2.6±0.1[8] R☉
Luminosity	45.3+3.1 −3.0[3] L☉
Surface gravity (log g)	4.1[9] cgs
Temperature	9,500[9] K
Metallicity [Fe/H]	−0.01[10] dex
Rotational velocity (v sin i)	152±13[11] km/s
Age	547[10] Myr
Other designations
η Oct, 11 G. Octantis[12], CPD−83°386, FK5 1664, GC 15164, HD 96124, HIP 53702, HR 4312, SAO 258600[13]
Database references
SIMBAD	data

Eta Octantis has a stellar classification of A1 Va,^[4] indicating that it is an ordinary A-type main sequence star. At present it has 2.37 times the Sun's mass^[3] and 2.6 times the Sun's radius.^[8] It shines with a luminosity of 45 L_☉^[3] from its photosphere at an effective temperature of 9,500 K, giving a white hue.^[9] Eta Octantis is a rapidly rotating star, with a projected rotational velocity of 152 km/s,^[11] and is estimated to be 547 million years old,^[10] having completed 72% of its main sequence lifetime.^[3]