Chi Octantis

Chi Octantis, Latinized from χ Octantis, is a solitary star^[14] located in the southern circumpolar constellation Octans. It is faintly visible to the naked eye as an orange-hued star with an apparent magnitude of 5.28.^[2] The object is located relatively close at a distance of 261 light years based on Gaia EDR3 parallax measurements,^[1] but it is receding with a heliocentric radial velocity 33.6 km/s.^[5] At its current distance, Chi Octantis' brightness is diminished by 0.24 magnitudes due to interstellar dust.^[15] It has an absolute magnitude of +0.81.^[6]

χ Octantis

Location of χ Oct (circled)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Octans
Right ascension	18h 54m 47.14062s[1]
Declination	−87° 36′ 21.0359″[1]
Apparent magnitude (V)	5.28±0.01[2]
Characteristics
Spectral type	K3 III[3]
U−B color index	+1.60[4]
B−V color index	+1.28[4]
Astrometry
Radial velocity (Rv)	33.6±3.1[5] km/s
Proper motion (μ)	RA: −36.555 mas/yr[1] Dec.: −135.715 mas/yr[1]
Parallax (π)	12.5114±0.0730 mas[1]
Distance	261 ± 2 ly (79.9 ± 0.5 pc)
Absolute magnitude (MV)	+0.81[6]
Details
Mass	1.25±0.33[7] M☉
Radius	15.6±0.8[8] R☉
Luminosity	73.6±0.7[9] L☉
Surface gravity (log g)	2.19[10] cgs
Temperature	4,266+99 −97[7] K
Metallicity [Fe/H]	+0.10[10] dex
Rotational velocity (v sin i)	<1[11] km/s
Other designations
χ Oct, 30 G. Octantis[12], CD−87°92, CPD−87°274, FK5 922, GC 25207, HD 164461, HIP 92824, HR 6721, SAO 258799[13]
Database references
SIMBAD	data

Chi Octantis is an evolved red giant with a stellar classification of K3 III.^[3] It has 125% the mass of the Sun and an enlarged radius of 14.45 R_☉ due to its evolved state.^[7] It radiates 73.6 times the luminosity of the Sun^[9] from its photosphere at an effective temperature of 4,266 K.^[7] Chi Octantis is metal enriched with an iron abundance 126% that of the Sun ([Fe/H] = +0.10)^[10] and spins slowly with a projected rotational velocity less than 1 km/s⁻¹.^[11]