HD 91942

This article is about r Carinae. For the variable star, see R Carinae.

HD 91942 is a single^[9] variable star in the constellation Carina. It has the Bayer designation r Carinae, while HD 91942 is the identifier from the Henry Draper catalogue. This orange-hued object is visible to the naked eye with an apparent visual magnitude of 4.45.^[2] Based on parallax measurements, it is located at a distance of approximately 1,180 light years from the Sun.^[1] The star has an absolute magnitude of −3.77,^[2] and is drifting further away with a radial velocity of +9.9 km/s.^[2]

HD 91942

Observation data Epoch J2000.0      Equinox J2000.0
Constellation	Carina
Right ascension	10h 35m 35.29721s[1]
Declination	−57° 33′ 27.4835″[1]
Apparent magnitude (V)	4.45[2]
Characteristics
Evolutionary stage	Bright giant[3]
Spectral type	K3II-IIb[4]
B−V color index	1.604±0.004[2]
Variable type	Suspected[5]
Astrometry
Radial velocity (Rv)	+9.9±0.7[2] km/s
Proper motion (μ)	RA: −15.93[1] mas/yr Dec.: +0.49[1] mas/yr
Parallax (π)	2.77±0.17 mas[1]
Distance	1,180 ± 70 ly (360 ± 20 pc)
Absolute magnitude (MV)	−3.77[2]
Details
Mass	8.1±0.7[6] M☉
Radius	155.5+5.6 −11.3[7] R☉
Luminosity	5,485±693[7] L☉
Surface gravity (log g)	2.0[3] cgs
Temperature	3,983+152 −69[7] K
Metallicity [Fe/H]	0.0[3] dex
Rotational velocity (v sin i)	5.8[3] km/s
Age	35.7±8.3[6] Myr
Other designations
r Car, NSV 4904, CPD−56°3544, FK5 393, GC 14570, HD 91942, HIP 51849, HR 4159, SAO 238222[8]
Database references
SIMBAD	data

This object is a massive, aging bright giant with a stellar classification of K3II-IIb.^[4] It is a suspected variable star that fluctuates in magnitude by an amplitude of 0.05 in the B-band of the UBV photometric system.^[5] With the supply of hydrogen exhausted at its core, it has evolved of the main sequence and cooled and expanded to 156^[7] times the Sun's radius. It is an estimated 36^[6] million years old with eight^[6] times the mass of the Sun. It is radiating around 5,500^[7] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 3,983 K.^[7]