56 Orionis

56 Orionis is a single,^[10] variable star in the equatorial constellation of Orion. It has an orange hue and is faintly visible to the naked eye with an apparent visual magnitude that fluctuates around 4.76.^[2] The star is located at a distance of approximately 1,130^[1] light years from the Sun based on parallax.^[1] It is drifting further away with a radial velocity of +11 km/s.^[1] The star has a peculiar velocity of 19.0+2.9
−3.1 km/s relative to its neighbors, and may be a runaway star.^[6]

56 Orionis

Location of 56 Orionis (circled)
Observation data Epoch J2000      Equinox J2000
Constellation	Orion
Right ascension	05h 52m 26.43865s[1]
Declination	+01° 51′ 18.5021″[1]
Apparent magnitude (V)	4.76[2] (4.73 to 4.78)[3]
Characteristics
Spectral type	K2-IIb[4]
U−B color index	+1.46[5]
B−V color index	+1.382±0.005[2]
Astrometry
Radial velocity (Rv)	+11.27±0.14[1] km/s
Proper motion (μ)	RA: –6.942[1] mas/yr Dec.: –8.355[1] mas/yr
Parallax (π)	2.8794 ± 0.1854 mas[1]
Distance	1,130 ± 70 ly (350 ± 20 pc)
Absolute magnitude (MV)	−3.14[2]
Details
Mass	6.4±0.7[6] M☉
Radius	92.21+4.27 −6.72[1] R☉
Luminosity	2,547±187[1] L☉
Surface gravity (log g)	0.91[7] cgs
Temperature	4,270+165 −96[1] K
Metallicity [Fe/H]	−0.07[7] dex
Rotational velocity (v sin i)	3.5[8] km/s
Age	60.7±18.4[6] Myr
Other designations
56 Ori, NSV 2690, BD+01°1151, FK5 2444, GC 7380, HD 39400, HIP 27750, HR 2037, SAO 113220, CCDM J05524+0151, WDS 05524+0151[9]
Database references
SIMBAD	data

This object is a bright giant star with a stellar classification of K2-IIb.^[4] It is a suspected variable star of unknown type with a brightness that has been measured varying from 4.73 down to 4.78.^[3] The star is about 61^[6] million years old with 6.4^[6] times the mass of the Sun and is spinning with a projected rotational velocity of 3.5.^[8] Having exhausted the supply of hydrogen at its core, the star has expanded to 92^[1] times the radius of the Sun. It is radiating 2,547 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,270 K.^[1]

It has one reported visual companion, designated component B, with magnitude 13.5 and angular separation 42.9″.^[11]

References

1. 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. 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. Vizier catalog entry
3. Samus, N. N.; Kazarovets, E. V.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 61 (1) (5.1 ed.): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869. Retrieved 2019-11-23.
4. Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373.
5. Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers. 42 (2): 443. Bibcode:2014JAVSO..42..443M.Vizier catalog entry
6. Tetzlaff, N.; et al. (January 2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. S2CID 118629873.
7. Earle Luck, R. (2014). "Parameters and Abundances in Luminous Stars". The Astronomical Journal. 147 (6): 137. Bibcode:2014AJ....147..137L. doi:10.1088/0004-6256/147/6/137.
8. De Medeiros, J. R.; Mayor, M. (1999). "A catalog of rotational and radial velocities for evolved stars". Astronomy and Astrophysics Supplement Series. 139 (3): 433. arXiv:astro-ph/0608248. Bibcode:1999A&AS..139..433D. doi:10.1051/aas:1999401. Vizier catalog entry
9. "56 Ori". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-11-22.
10. Eggleton, P. P.; Tokovinin, A. A. (September 2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869–879. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
11. Mason, Brian D.; et al. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. Vizier catalog entry