15 Orionis

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15 Orionis
Orion constellation map.svg
Red circle.svg
Location of 15 Orionis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Orion
Right ascension  05h 09m 41.96481s[1]
Declination 15° 35′ 49.9051″[1]
Apparent magnitude (V) 4.82[2]
Spectral type F2IV[3]
U−B color index +0.19[2]
B−V color index +0.32[2]
Radial velocity (Rv)+28.79[4] km/s
Proper motion (μ) RA: −3.105[1] mas/yr
Dec.: –3.444[1] mas/yr
Parallax (π)9.5097 ± 0.2951[1] mas
Distance340 ± 10 ly
(105 ± 3 pc)
Absolute magnitude (MV)−0.04[5]
15 Ori A
Mass3.42±0.67[6] M
Radius5.9[7] R
Luminosity300[6] L
Surface gravity (log g)3.75[8] cgs
[6] K
Metallicity [Fe/H]+0.21[8] dex
Rotational velocity (v sin i)60[6] km/s
Other designations
15 Ori, BD+15°752, GC 6306, HD 33276, HIP 24010, HR 1676, SAO 94359, CCDM J05097+1536AB, WDS J05097+1536AB
Database references

15 Orionis is a suspected astrometric binary[9] star system in the equatorial constellation of Orion, near the border with Taurus. It is visible to the naked eye as a faint, yellow-white hued star with an apparent visual magnitude of 4.82.[2] The system is approximately 340 light years away from the Sun based on parallax. It is moving further from the Earth with a heliocentric radial velocity of +29 km/s,[4] having come to within 69 light-years some three million years ago.[5]

The primary component is an early F-type subgiant star with a stellar classification of F2 IV,[3] a star that has exhausted the hydrogen at its core and has begun to evolve into a giant. It has 3.42[6] times the mass of the Sun and 5.9[7] times the Sun's radius. The star still has a relatively high rotation rate, showing a projected rotational velocity of 60 km/s.[6] It is radiating 300 times the luminosity of the Sun from its expanding photosphere at an effective temperature of 7,161 K.[6]

It has one suspected companion, component B, at a separation of 0.3".[10]


  1. ^ a b c d e 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 Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  3. ^ a b Hoffleit, D.; Warren, W. H. (1995). "VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H. 5050. Bibcode:1995yCat.5050....0H.
  4. ^ a b Massarotti, Alessandro; Latham, David W.; Stefanik, Robert P.; Fogel, Jeffrey (2008). "Rotational and Radial Velocities for a Sample of 761 Hipparcos Giants and the Role of Binarity". The Astronomical Journal. 135: 209. Bibcode:2008AJ....135..209M. doi:10.1088/0004-6256/135/1/209.
  5. ^ a b 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. Vizier catalog entry
  6. ^ a b c d e f g Zorec, J.; Royer, F.; Asplund, Martin; Cassisi, Santi; Ramirez, Ivan; Melendez, Jorge; Bensby, Thomas; Feltzing, Sofia (2012). "Rotational velocities of A-type stars. IV. Evolution of rotational velocities". Astronomy and Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691.
  7. ^ a b Allende Prieto, C.; Lambert, D. L. (1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: Masses, radii and effective temperatures". Astronomy and Astrophysics. 352: 555. arXiv:astro-ph/9911002. Bibcode:1999A&A...352..555A. Vizier catalog entry
  8. ^ a b Wu, Yue; Singh, H. P.; Prugniel, P.; Gupta, R.; Koleva, M. (2010). "Coudé-feed stellar spectral library – atmospheric parameters". Astronomy & Astrophysics. 525: A71. arXiv:1009.1491. Bibcode:2011A&A...525A..71W. doi:10.1051/0004-6361/201015014.
  9. ^ 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.
  10. ^ Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (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