23 Orionis

23 Orionis is a double star located around 1,200 light-years (370 parsecs)^[1] away from the Sun in the equatorial constellation of Orion.^[12] It is visible to the naked eye as a dim, blue-white-hued point of light with a combined apparent visual magnitude of 4.99.^[2] The pair are moving away from the Earth with a heliocentric radial velocity of +18 km/s,^[5] and they are members of the Orion OB1 association, subgroup 1a.^[13]

23 Orionis

Observation data Epoch J2000      Equinox J2000
Constellation	Orion
Right ascension	05h 22m 50.00474s[1]
Declination	+03° 32′ 39.9770″[1]
Apparent magnitude (V)	4.99[2] (4.95 + 6.76)[3]
Characteristics
Evolutionary stage	main sequence
Spectral type	B1V + B3V[4]
B−V color index	−0.096±0.004[2]
Astrometry
Absolute magnitude (MV)	−2.93[2]
23 Ori A
Radial velocity (Rv)	+18.0±3.7[5] km/s
Proper motion (μ)	RA: −2.414[1] mas/yr Dec.: +1.230[1] mas/yr
Parallax (π)	2.7199 ± 0.3155 mas[1]
Distance	approx. 1,200 ly (approx. 370 pc)
23 Ori B
Radial velocity (Rv)	28[6] km/s
Proper motion (μ)	RA: +1.275[7] mas/yr Dec.: −0.552[7] mas/yr
Parallax (π)	2.5579 ± 0.0864 mas[7]
Distance	1,280 ± 40 ly (390 ± 10 pc)
Details
23 Ori A
Mass	12.5±0.6[8] M☉
Radius	6.97[9] R☉
Luminosity	26,546[10] L☉
Surface gravity (log g)	4.078±0.045[11] cgs
Temperature	25,400[10] K
Rotational velocity (v sin i)	350[4] km/s
Age	15.4±0.6[8] Myr
23 Ori B
Mass	6.6±0.1[8] M☉
Radius	4.71[9] R☉
Luminosity	1,620[10] L☉
Temperature	18,700[10] K
Rotational velocity (v sin i)	370[4] km/s
Age	22.8±2.3[8] Myr
Other designations
23 Ori, SAO 112697, WDS J05228+0333[12]
A: BD+03°871, HD 35149, HIP 25142, HR 1770, SAO 112697
B: BD+03°872, HD 35148, HIP 25145, SAO 112699
Database references
SIMBAD	data
	B

Howe and Clarke (2009) catalog this as a double-lined spectroscopic binary star system^[14] with a wide projected separation of 9,460 AU.^[9] As of 2018, they had an angular separation of 31.9″ along a position angle of 30°.^[3] The brighter member, component A, is a B-type main-sequence star with a stellar classification of B1V. The secondary, component B, is of class B3V.^[4] Both stars are spinning rapidly.^[4]

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.
3. Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
4. Levato, H. (1975), "Rotational velocities and spectral types for a sample of binary systems", Astronomy and Astrophysics, 19: 91, Bibcode:1975A&AS...19...91L.
5. de Bruijne, J. H. J.; Eilers, A.-C. (October 2012), "Radial velocities for the HIPPARCOS-Gaia Hundred-Thousand-Proper-Motion project", Astronomy & Astrophysics, 546: 14, arXiv:1208.3048, Bibcode:2012A&A...546A..61D, doi:10.1051/0004-6361/201219219, S2CID 59451347, A61.
6. Morrell, Nidia; Levato, Hugo (1991), "Spectroscopic Binaries in the Orion OB1 Association", The Astrophysical Journal Supplement Series, 75: 965, Bibcode:1991ApJS...75..965M, doi:10.1086/191556.
7. 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.
8. 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.
9. Howe, K. S.; Clarke, C. J. (January 2009), "An analysis of v sin (i) correlations in early-type binaries", Monthly Notices of the Royal Astronomical Society, 392 (1): 448–454, Bibcode:2009MNRAS.392..448H, doi:10.1111/j.1365-2966.2008.14073.x.
10. Hohle, M. M.; et al. (2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, arXiv:1003.2335, Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355, S2CID 111387483.
11. Huang, Wenjin; et al. (October 2010), "A Stellar Rotation Census of B Stars: From ZAMS to TAMS", The Astrophysical Journal, 722 (1): 605–619, arXiv:1008.1761, Bibcode:2010ApJ...722..605H, doi:10.1088/0004-637X/722/1/605, S2CID 118532653.
12. "23 Ori". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-06-08.
13. Welty, Daniel E.; et al. (October 1999), "The Diffuse Interstellar Clouds toward 23 Orionis", The Astrophysical Journal Supplement Series, 124 (2): 465–501, arXiv:astro-ph/9905234, Bibcode:1999ApJS..124..465W, doi:10.1086/313263, S2CID 13966185.
14. Chini, R.; et al. (2012), "A spectroscopic survey on the multiplicity of high-mass stars", Monthly Notices of the Royal Astronomical Society, 424 (3): 1925–1929, arXiv:1205.5238, Bibcode:2012MNRAS.424.1925C, doi:10.1111/j.1365-2966.2012.21317.x, S2CID 119120749.