Psi Octantis

Psi Octantis, Latinized from ψ Octantis, is a solitary^[12] star in the southern circumpolar constellation Octans. It has an apparent magnitude of 5.47,^[2] allowing it to be seen with the naked eye under ideal conditions. The star is relatively close at a distance of 126 light years^[1] but is receding with a heliocentric radial velocity of 17 km/s.^[6]

ψ Octantis

Location of ψ Oct (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Octans
Right ascension	22h 17m 50.5954s[1]
Declination	−77° 30′ 41.599″[1]
Apparent magnitude (V)	5.47±0.01[2]
Characteristics
Evolutionary stage	main sequence[1]
Spectral type	F0IIp[3] (F4V:kA5)[4]
U−B color index	+0.12[5]
B−V color index	+0.31[5]
Astrometry
Radial velocity (Rv)	17.0±1.6[6] km/s
Proper motion (μ)	RA: −37.392 mas/yr[1] Dec.: +13.788 mas/yr[1]
Parallax (π)	25.7575±0.0505 mas[1]
Distance	126.6 ± 0.2 ly (38.82 ± 0.08 pc)
Absolute magnitude (MV)	+2.56[7]
Details
Mass	1.49±0.07[8] M☉
Radius	1.74±0.04[8] R☉
Luminosity	7.82[7] L☉
Surface gravity (log g)	4.13±0.05[8] cgs
Temperature	7,244[8] K
Metallicity [Fe/H]	−0.04[9] dex
Age	1.41[9] Gyr
Other designations
ψ Oct, 60 G. Octantis[10], CPD−78°1442, FK5 3779, GC 31133, HD 210853, HIP 110078, HR 8471, SAO 258020[11]
Database references
SIMBAD	data

Psi Octantis has a spectral classification of F0IIp, suggesting that it is a bright giant but with peculiarities. Other assessments give a luminosity class of III (giant),^[13] III-IV (intermediate between giant and subgiant),^[14] or V: (approximately main sequence).^[4] One paper gives a spectral class of F4V:kA5, indicating that it is a probable F-type main-sequence star with the calcium K-lines of an A5 star, including sharp absorption lines of metals.^[4] Analysis of its evolutionary stage show it to be a somewhat evolved main sequence star.^[1]

It has 149% the mass of the Sun and 1.74 times the radius of the Sun.^[8] It shines at 7.82 times the luminosity of the Sun^[7] from its photosphere at an effective temperature of 7,244 K,^[8] giving it a yellowish white glow. Psi Octantis has an iron abundance 91% that of the Sun and is estimated to be 1.41 billion years old.^[9]