HD 36780
Orion Belt 2009-01-29.jpg
Red circle.svg
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]
Evolutionary stage giant
Spectral type K4 III[3]
U−B color index +1.87[4]
B−V color index +1.535±0.008[2]
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]
Distance534 ± 10 ly
(164 ± 3 pc)
Absolute magnitude (MV)−0.65[2]
[1] R
Luminosity243.3±5.2[1] L
Other designations
BD–01°950, GC 6894, HD 36780, HIP 26108, HR 1874, SAO 132270[5]
Database references

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]

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]


  1. ^ a b c d e f g h i j k Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  2. ^ a b c d e Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  3. ^ a b Houk, N.; Swift, C. (1999). "Michigan catalogue of two-dimensional spectral types for the HD Stars". Michigan Spectral Survey. 5. Bibcode:1999MSS...C05....0H.
  4. ^ Johnson, H. L. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99. Bibcode:1966CoLPL...4...99J.
  5. ^ "HD 36780". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 13 March 2017.