HD 40091

A light curve for HD 40091, plotted from Hipparcos data [1]
Observation data Epoch J2000.0       Equinox J2000.0 ( ICRS)
Constellation	Columba
Right ascension	05h 54m 52.48300s [2]
Declination	−39° 57′ 28.2946″ [2]
Apparent magnitude (V)	5.54±0.01 [3]
Characteristics
Spectral type	M0 III [4]
U−B color index	+1.85 [5]
B−V color index	+1.51 [5]
Variable type	suspected [6]
Astrometry
Radial velocity (Rv)	114±2 [7] km/s
Proper motion (μ)	RA: −11.977  mas/ yr [2] Dec.: +21.203  mas/ yr [2]
Parallax (π)	6.5078 ± 0.1112  mas [2]
Distance	501 ± 9  ly (154 ± 3  pc)
Absolute magnitude (MV)	−0.4 [8]
Details
Mass	1.21 [9]  M☉
Radius	52.43 [10]  R☉
Luminosity	392 [11]  L☉
Surface gravity (log g)	1.31 [9]  cgs
Temperature	3,969±122 [12]  K
Metallicity [Fe/H]	+0.14 [9]  dex
Other designations
60 G. Columbae [13], NSV 16734, CD−39°2260, CPD−39°789, FK5 2449, GC 7471, HD 40091, HIP 27955, HR 2082, SAO 196309 [14]
Database references
SIMBAD	data

HD 40091, also known as HR 2082, is a solitary star ^[15] located in the southern constellation Columba, the dove. It has an apparent magnitude of 5.54, ^[3] making it faintly visible to the naked eye under ideal conditions. Based on parallax measurements from the Gaia spacecraft, the object is estimated to be 501 light years distant. ^[2] However, it is rapidly receding with a high heliocentric radial velocity of 114  km/s. ^[7]

This is an evolved red giant with a stellar classification of M0 III. ^[4] It has 121% the mass of the Sun ^[9] but has expanded to 52.43 times its girth. ^[10] It radiates 392 times the luminosity of the Sun ^[11] from its enlarged photosphere at an effective temperature of 3,969  K, ^[12] giving it a red hue. HD 40091 is slightly metal enriched, having an iron abundance 38% above solar levels. ^[9]

HD 40091 is found to vary between 5.64 and 5.68 in the Hipparcos passband, but it is not confirmed to be a variable star. Therefore, it is catalogued in the GCVS as a suspected variable. ^[6]