72 Leonis

72 Leonis is a single[9] variable star in the zodiac constellation of Leo, located roughly 1,000 light years away from the Sun.[1] It has the variable star designation FN Leonis; 72 Leonis is the Flamsteed designation. In Chinese astronomy, 72 Leonis is called 虎賁, Pinyin: Hǔbēn, meaning Emperor’s Bodyguard, because this star is marking itself and stands alone in the Emperor’s Bodyguard asterism, Supreme Palace enclosure mansion (see : Chinese constellation).[10]

72 Leonis
Observation data
Epoch J2000      Equinox J2000
Constellation Leo
Right ascension  11h 15m 12.22709s[1]
Declination +23° 05′ 43.8373″[1]
Apparent magnitude (V) 4.63[2]
Characteristics
Spectral type M3 IIb[3]
B−V color index 1.657±0.003[4]
Variable type LC[5]
Astrometry
Radial velocity (Rv)14.76±0.21[4] km/s
Proper motion (μ) RA: −25.56[1] mas/yr
Dec.: −6.00[1] mas/yr
Parallax (π)3.40 ± 0.65[1] mas
Distanceapprox. 1,000 ly
(approx. 290 pc)
Absolute magnitude (MV)−2.69[4]
Details
Mass3.11[6] M☉
Radius195[6] R☉
Luminosity5,770[7] L☉
Surface gravity (log g)1.16[6] cgs
Temperature3,613±48[6] K
Metallicity [Fe/H]−0.03[6] dex
Age400[6] Myr
Other designations
72 Leo, FN Leo, BD+23°2322, FK5 2897, HD 97778, HIP 54951, HR 4362, SAO 81736[8]
Database references
SIMBADdata

This object is visible to the naked eye as a red-hued star with an apparent visual magnitude of 4.56.[4] It is an evolved bright giant with a stellar classification of M3 IIb and was listed as a spectral standard star for that class.[3] The star is classified as an irregular variable of type LC, ranging from Hipparcos magnitude 4.56 down to 4.64.[5] It has a radius 162 to 179[11] times that of the Sun and radiates 5,407[12] times the Sun's luminosity at an effective temperature of around 3,734 K.[13] The star is moving away from the Earth with a heliocentric radial velocity of 15 km/s.[4]

References
  1. 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.
  2. 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. 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.
  4. 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.
  5. Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S.
  6. Baines, Ellyn K.; Armstrong, J. Thomas; Schmitt, Henrique R.; Zavala, R. T.; Benson, James A.; Hutter, Donald J.; Tycner, Christopher; Van Belle, Gerard T. (2018), "Fundamental Parameters of 87 Stars from the Navy Precision Optical Interferometer", The Astronomical Journal, 155 (1): 30, arXiv:1712.08109, Bibcode:2018AJ....155...30B, doi:10.3847/1538-3881/aa9d8b.
  7. McDonald, I.; Zijlstra, A. A.; Watson, R. A. (2017), "Fundamental parameters and infrared excesses of Tycho-Gaia stars", Monthly Notices of the Royal Astronomical Society, 471 (1): 770, arXiv:1706.02208, Bibcode:2017MNRAS.471..770M, doi:10.1093/mnras/stx1433.
  8. "72 Leo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-02-09.
  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. Leo the Lion, Ian Ridpath's Startales, retrieved 2019-02-10.
  11. Kaler, James B. (May 11, 2012), "72 Leonis", stars.astro.illinois.edu, retrieved 2017-10-09.
  12. McDonald, I.; et al. (2012), "Fundamental parameters and infrared excesses of Hipparcos stars", Monthly Notices of the Royal Astronomical Society, 427: 343, arXiv:1208.2037, Bibcode:2012MNRAS.427..343M, doi:10.1111/j.1365-2966.2012.21873.x.
  13. Dyck, H. M.; et al. (1998), "Radii and Effective Temperatures for K and M Giants and Supergiants. II", The Astronomical Journal, 116 (2): 981, Bibcode:1998AJ....116..981D, CiteSeerX 10.1.1.24.1889, doi:10.1086/300453.
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