HD 36780

HD 36780 is a star located in Orion's belt, within the equatorial constellation of Orion. It has an orange hue and is dimly visible to the naked eye with an apparent visual magnitude of +5.92.[2] The distance to this object is approximately 534 light years based on parallax.[1] It is drifting away from the Sun with a radial velocity of 84 km/s,[1] having come to within 185.6 light-years some 2.1 million years ago.[2]

HD 36780

Location of HD 36780 (circled) in the Orion's Belt region Credit: Martin Mutti
Observation data Epoch J2000      Equinox J2000
Constellation	Orion
Right ascension	05h 34m 04.04714s[1]
Declination	−01° 28′ 12.8681″[1]
Apparent magnitude (V)	+5.92[2]
Characteristics
Evolutionary stage	giant
Spectral type	K4 III[3]
U−B color index	+1.87[4]
B−V color index	+1.535±0.008[2]
Astrometry
Radial velocity (Rv)	83.80±0.30[1] km/s
Proper motion (μ)	RA: −7.904[1] mas/yr Dec.: −31.852[1] mas/yr
Parallax (π)	6.1048 ± 0.1096 mas[1]
Distance	534 ± 10 ly (164 ± 3 pc)
Absolute magnitude (MV)	−0.65[2]
Details
Radius	30.8+2.1 −4.2[1] R☉
Luminosity	243.3±5.2[1] L☉
Temperature	4,108+315 −135 K
Other designations
BD–01°950, GC 6894, HD 36780, HIP 26108, HR 1874, SAO 132270[5]
Database references
SIMBAD	data

This is an aging giant star with a stellar classification of K4 III.[3] After exhausting the supply of hydrogen at its core, the star cooled and expanded off the main sequence. At present it has around 31 times the girth of the Sun. It is radiating 243 times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,108 K.[1]