Rho Octantis

Not to be confused with R Octantis.

Rho Octantis, Latinized from ρ Octantis, is a star located in the southern circumpolar constellation Octans. With an apparent magnitude of 5.57,^[2] its faintly visible to the naked eye under ideal conditions. The star is located 215 light years away from the Solar System,^[1] but is drifting closer with a radial velocity of −11 km/s.^[5]

ρ Octantis

Location of ρ Octantis (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Octans
Right ascension	15h 43m 16.927s[1]
Declination	−84° 27′ 54.99″[1]
Apparent magnitude (V)	5.57±0.01[2]
Characteristics
Spectral type	A1/2 V[3]
U−B color index	+0.08[4]
B−V color index	+0.11[4]
Astrometry
Radial velocity (Rv)	−11±10[5] km/s
Proper motion (μ)	RA: +131.101[1] mas/yr Dec.: +96.007[1] mas/yr
Parallax (π)	15.1565±0.0796 mas[1]
Distance	215 ± 1 ly (66.0 ± 0.3 pc)
Absolute magnitude (MV)	+1.47[6]
Details
Mass	1.99[7] M☉
Radius	2.19±0.07[8] R☉
Luminosity	21±1[8] L☉
Surface gravity (log g)	4.06±0.14[9] cgs
Temperature	8,881±302[9] K
Rotational velocity (v sin i)	128[10] km/s
Age	431[7] Myr
Other designations
ρ Octantis, 24 G. Octantis, CPD–84 510, HD 13733, HIP 76996, HR 5729, SAO 258731, WDS J15433-8428A
Database references
SIMBAD	data

Rho Octantis has a classification of A1/2 V, which states its a star with the traits of an A1 and A2 main-sequence star. It has nearly twice the mass of the Sun,^[7] and has a radius of 2.19 solar radii.^[8] The star radiates at a luminosity 21 times greater than the Sun from its photosphere^[8] at an effective temperature of 8,881 K,^[9] which gives it a white hue. Like many A-type stars, Rho Octantis rotates rapidly, with a projected rotational velocity of 128 km/s;^[10] it is 431 million years old.^[7] Rho Octantis has a common proper motion K0 companion 65.7” away.^[11]