Astronomy:Chi Leonis

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Short description: Double star system in the constellation Leo
χ Leonis
Location of χ Leonis (circled in red)
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Leo
Right ascension  11h 05m 01.02754s[1]
Declination +07° 20′ 09.6235″[1]
Apparent magnitude (V) 4.63[2]
Characteristics
Evolutionary stage Main sequence[3]
Spectral type F2III-IVv[4]
U−B color index +0.06[2]
B−V color index +0.33[2]
Astrometry
Radial velocity (Rv)+4.7[5] km/s
Proper motion (μ) RA: −344.28[1] mas/yr
Dec.: −47.65[1] mas/yr
Parallax (π)34.49 ± 0.20[1] mas
Distance94.6 ± 0.5 ly
(29.0 ± 0.2 pc)
Absolute magnitude (MV)+2.31[6]
Details
Mass1.62[7] M☉
Radius1.99[8] R☉
Luminosity9.9[6] L☉
Surface gravity (log g)4.02[7] cgs
Temperature7022±80[7] K
Metallicity [Fe/H]+0.03[7] dex
Rotational velocity (v sin i)25±1[4] km/s
Age1.40[7] Gyr
Other designations
χ Leo, 63 Leo, BD+08°2455, FK5 418, HD 96097, HIP 54182, HR 4310, SAO 118648[9]
Database references
SIMBADdata

Chi Leonis, Latinized from χ Leonis, is a double star in the constellation Leo. It is visible to the naked eye with an apparent visual magnitude of 4.63.[2] The distance to this star, as determined using parallax measurements,[1] is around 95 light years. It has an annual proper motion of 346 mas.[10]

This is most likely a binary star system.[11] The primary component has a stellar classification of F2III-IVv, which at first would classify it as a F-type star between the giant and subgiant evolutionary stages,[4] but evolutionary models suggest the star is instead in the main sequence.[3][12] It has an estimated 162% of the Sun's mass[7] and nearly twice the Sun's radius.[8] The companion is a magnitude 11.0 star at an angular separation of 4.1″ along a position angle of 264°, as of 1990.[13]

Observation

On 18 October 2015, it was occulted by Mars as viewed from East Asia and Japan.[14]: 165 

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 van Leeuwen, F. (2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics 474 (2): 653–664, doi:10.1051/0004-6361:20078357, Bibcode: 2007A&A...474..653V. 
  2. ↑ 2.0 2.1 2.2 2.3 Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data (SIMBAD), Bibcode: 1986EgUBV........0M. 
  3. ↑ 3.0 3.1 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  4. ↑ 4.0 4.1 4.2 Royer, F. et al. (October 2002), "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i", Astronomy and Astrophysics 393: 897–911, doi:10.1051/0004-6361:20020943, Bibcode: 2002A&A...393..897R. 
  5. ↑ Wilson, R. E. (1953), "General Catalogue of Stellar Radial Velocities", Carnegie Institute Washington D.C. Publication (Carnegie Institute of Washington, D.C.), Bibcode: 1953GCRV..C......0W. 
  6. ↑ 6.0 6.1 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A. 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 7.5 Casagrande, L. et al. (2011), "New constraints on the chemical evolution of the solar neighbourhood and Galactic disc(s). Improved astrophysical parameters for the Geneva-Copenhagen Survey", Astronomy & Astrophysics 530 (A138): 21, doi:10.1051/0004-6361/201016276, Bibcode: 2011A&A...530A.138C. 
  8. ↑ 8.0 8.1 Rachford, Brian L.; Foight, Dillon R. (June 2009), "Chromospheric Variability in Early F-Type Stars", The Astrophysical Journal 698 (1): 786–802, doi:10.1088/0004-637X/698/1/786, Bibcode: 2009ApJ...698..786R. 
  9. ↑ "* chi Leo". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=%2A+chi+Leo. 
  10. ↑ Lépine, Sébastien; Shara, Michael M. (March 2005), "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)", The Astronomical Journal 129 (3): 1483–1522, doi:10.1086/427854, Bibcode: 2005AJ....129.1483L. 
  11. ↑ 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. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode: 2008MNRAS.389..869E. 
  12. ↑ "20.2.1 astrophysical_parameters‣ 20.2 Astrophysical parameter tables ‣ Chapter 20 Datamodel description ‣ Part V Gaia archive ‣ Gaia Data Release 3 Documentation release 1.3". https://gea.esac.esa.int/archive/documentation/GDR3/Gaia_archive/chap_datamodel/sec_dm_astrophysical_parameter_tables/ssec_dm_astrophysical_parameters.html#astrophysical_parameters-evolstage_flame. 
  13. ↑ Mason, B. D. et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal 122 (6): 3466–3471, doi:10.1086/323920, Bibcode: 2001AJ....122.3466M. 
  14. ↑ Meeus, Jan (2002). "Mutual occultations of planets". More Mathematical Astronomy Morsels. pp. 174–185. ISBN 0943396743. https://falakmu.id/khgt/dokumen/More%20mathematical%20astronomy%20morsels%20(Jean%20Meeus)%20(Z-Library).pdf.