31 Persei


31 Persei is a single[13] star in the northern constellation of Perseus. It is visible to the naked eye as a dim, blue-white hued point of light with an apparent visual magnitude of 5.05.[2] This star is located around 172 parsecs (560 ly) away from the Sun,[14] and it is drifting closer with a radial velocity of −1.6 km/s.[5] It is a likely member of the Alpha Persei Cluster.[15]

31 Persei
Perseus constellation map.svg
Red circle.svg
Location of 31 Persei (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Perseus
Right ascension 03h 19m 07.63796s[1]
Declination 50° 05′ 41.8724″[1]
Apparent magnitude (V) 5.05[2]
Spectral type B5V[3]
U−B color index −0.53[4]
B−V color index −0.06[4]
Radial velocity (Rv)−1.60[5] km/s
Proper motion (μ) RA: +23.580[1] mas/yr
Dec.: −23.322[1] mas/yr
Parallax (π)5.8399 ± 0.1792 mas[1]
Distance560 ± 20 ly
(171 ± 5 pc)
Absolute magnitude (MV)−1.44[6]
Mass4.647[7] M
Radius3.4[8] R
Luminosity950[6] L
Temperature15,301[6] K
Metallicity [Fe/H]0.00[9] dex
Rotational velocity (v sin i)260[10] km/s
Age234[11] Myr
Other designations
31 Per, BD+49°902, GC 3945, HD 20418, HIP 15444, HR 989, SAO 38714[12]
Database references

This object is a B-type main-sequence star with a stellar classification of B5V,[3] a massive star that is currently generating energy through hydrogen fusion at its core. It is around 234[9] million years old and spinning rapidly with a projected rotational velocity of 260 km/s.[10] The star has 4.6[7] times the mass of the Sun and about 3.4[8] times the Sun's radius. It is radiating 950[6] times the luminosity of the Sun from its photosphere at an effective temperature of 15,301 K.[6]


  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 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. ^ 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 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
  5. ^ a b Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. S2CID 119231169.
  6. ^ a b c d e Silaj, J.; Landstreet, J. D. (2014). "Accurate age determinations of several nearby open clusters containing magnetic Ap stars". Astronomy & Astrophysics. 566: A132. arXiv:1407.4531. Bibcode:2014A&A...566A.132S. doi:10.1051/0004-6361/201321468. S2CID 53370832.
  7. ^ a b Sheikhi, Najmeh; et al. (March 2016). "The binary fraction and mass segregation in Alpha Persei open cluster". Monthly Notices of the Royal Astronomical Society. 457 (1): 1028–1036. arXiv:1601.02186. Bibcode:2016MNRAS.457.1028S. doi:10.1093/mnras/stw059.
  8. ^ a b Pasinetti Fracassini, L. E.; et al. (February 2001). "Catalogue of Apparent Diameters and Absolute Radii of Stars (CADARS)". Astronomy and Astrophysics (Third ed.). 367 (2): 521–524. arXiv:astro-ph/0012289. Bibcode:2001A&A...367..521P. doi:10.1051/0004-6361:20000451. S2CID 425754.
  9. ^ a b Gontcharov, G. A. (2012). "Dependence of kinematics on the age of stars in the solar neighborhood". Astronomy Letters. 38 (12): 771–782. arXiv:1606.08814. Bibcode:2012AstL...38..771G. doi:10.1134/S1063773712120031. S2CID 118345778. Vizier catalog entry
  10. ^ a b Abt, Helmut A.; et al. (2002). "Rotational Velocities of B Stars". The Astrophysical Journal. 573 (1): 359–365. Bibcode:2002ApJ...573..359A. doi:10.1086/340590.
  11. ^ Gontcharov, G. A. (November 2012). "Spatial distribution and kinematics of OB stars". Astronomy Letters. 38 (11): 694–706. arXiv:1606.09028. Bibcode:2012AstL...38..694G. doi:10.1134/S1063773712110035. S2CID 119108982.
  12. ^ "31 Per". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-07-13.
  13. ^ 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.
  14. ^ Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600. Vizier catalog entry
  15. ^ Zuckerman, B.; et al. (June 2012). "Stellar Membership and Dusty Debris Disks in the α Persei Cluster". The Astrophysical Journal. 752 (1): 12. arXiv:1204.3950. Bibcode:2012ApJ...752...58Z. doi:10.1088/0004-637X/752/1/58. S2CID 119207634. 58.