7 Leonis Minoris

7 Leonis Minoris (7 LMi) is a star located in the northern constellation Leo Minor. It is also designated as HD 82087 and HR 3764. 7 LMi is faintly visible to the naked eye as a yellow-hued point of light with an apparent magnitude of 5.86.[2] Gaia DR3 parallax measurements imply a distance of 462 light-years[1] and it is currently receding with a heliocentric radial velocity of 1.7 km/s.[6] At its current distance, 7 LMi's brightness is diminished by 0.12 magnitudes due to interstellar extinction[13] and it has an absolute magnitude of −0.03[7]

7 Leonis Minoris
Location of 7 LMi on the map (circled)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Leo Minor
Right ascension 09h 30m 43.22705s[1]
Declination +33° 39′ 20.5700″[1]
Apparent magnitude (V) 5.86±0.01[2]
Characteristics
Evolutionary stage horizontal branch[3]
Spectral type G9 III[4]
B−V color index +1.05[5]
Astrometry
Radial velocity (Rv)1.7±0.9[6] km/s
Proper motion (μ) RA: −23.939 mas/yr[1]
Dec.: −48.160 mas/yr[1]
Parallax (π)7.0542 ± 0.1338 mas[1]
Distance462 ± 9 ly
(142 ± 3 pc)
Absolute magnitude (MV)−0.03[7]
Details
Mass2.74+0.24
−0.25[3] M☉
Radius13.41±0.68[8] R☉
Luminosity96.0+3.3
−3.6[1] L☉
Surface gravity (log g)2.49+0.07
−0.06[3] cgs
Temperature4,923±122[9] K
Metallicity [Fe/H]−0.03±0.10[10] dex
Rotational velocity (v sin i)0.24[11] km/s
Age575+201
−139[3] Myr
Other designations
7 LMi, AG+33°953, BD+34°1999, FK5 2755, GC 13112, HD 82087, HIP 46652, HR 3764, SAO 61529, CCDM J09307+3339A, WDS J09307+3339A, TIC 8855140[12]
Database references
SIMBADdata

There have been disagreements on the object's stellar classification. 7 LMi is either a G-type giant star with a class of either G8 or G9 III,[4] or it is a K-type giant with a class of K0 III.[14] It is most likely on the horizontal branch (95% fit),[3] generating energy via helium fusion at its core. It has 2.74 times the mass of the Sun but at the age of 575 million years,[3] it has expanded to 13.41 times the radius of the Sun.[8] It radiates 96 times the luminosity of the Sun[1] from its enlarged photosphere at an effective temperature of 4,923 K.[9] 7 LMi has a near solar metallicity at [Fe/H] = −0.03[10] and it spins very slowly with a projected rotational velocity of 0.24 km/s.[11]

7 LMi has two visual companions. AG +33°954 is a background star located much farther away than 7 LMi[15] and it is a close spectroscopic binary itself.[16]

7 Leonis Minoris' companions[17]
CompanionStellar classificationPA (deg)Separation (arcsec)Apparent magnitude
AG +33°954 (B)G8 IV-V[4]12561.39.7
CG5 V[4]21795.911.6

References
  1. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361. S2CID 17128864.
  3. Stock, Stephan; Reffert, Sabine; Quirrenbach, Andreas (August 2018). "Precise radial velocities of giant stars: X. Bayesian stellar parameters and evolutionary stages for 372 giant stars from the Lick planet search". Astronomy & Astrophysics. 616: A33. arXiv:1805.04094. Bibcode:2018A&A...616A..33S. doi:10.1051/0004-6361/201833111. ISSN 0004-6361. S2CID 247657118.
  4. Abt, H. A. (May 1986). "The ages and dimensions of Trapezium systems". The Astrophysical Journal. American Astronomical Society. 304: 688. Bibcode:1986ApJ...304..688A. doi:10.1086/164207. ISSN 0004-637X. S2CID 121295060.
  5. Haggkvist, L.; Oja, T. (1970). "Results of BV photometry 1969-70 (Uppsala refractor)". Private Communication. Bibcode:1970Priv.........0H. S2CID 231475662.
  6. Gontcharov, G. A. (November 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. eISSN 1562-6873. ISSN 1063-7737. S2CID 119231169.
  7. Anderson, E.; Francis, Ch. (May 2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331–346. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. eISSN 1562-6873. ISSN 1063-7737. S2CID 119257644.
  8. Kervella, P.; Thévenin, F.; Di Folco, E.; Ségransan, D. (October 2004). "The angular sizes of dwarf stars and subgiants: Surface brightness relations calibrated by interferometry". Astronomy & Astrophysics. 426 (1): 297–307. arXiv:astro-ph/0404180. Bibcode:2004A&A...426..297K. doi:10.1051/0004-6361:20035930. eISSN 1432-0746. ISSN 0004-6361.
  9. Stassun, Keivan G.; et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. eISSN 1538-3881. hdl:1721.1/124721. S2CID 166227927.
  10. Reffert, Sabine; Bergmann, Christoph; Quirrenbach, Andreas; Trifonov, Trifon; Künstler, Andreas (December 15, 2014). "Precise Radial Velocities of Giant Stars VII. Occurrence Rate of Giant Extrasolar Planets as a Function of Mass and Metallicity". Astronomy & Astrophysics. EDP Sciences. 574: A116. arXiv:1412.4634. Bibcode:2015A&A...574A.116R. doi:10.1051/0004-6361/201322360. ISSN 0004-6361. S2CID 59334290.
  11. Hekker, S.; Meléndez, J. (December 2007). "Precise radial velocities of giant stars: III. Spectroscopic stellar parameters". Astronomy & Astrophysics. 475 (3): 1003–1009. arXiv:0709.1145. Bibcode:2007A&A...475.1003H. doi:10.1051/0004-6361:20078233. ISSN 0004-6361. S2CID 10436552.
  12. "* 7 LMi". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved August 8, 2023.
  13. Gontcharov, George A.; Mosenkov, Aleksandr V. (28 September 2017). "Verifying reddening and extinction for Gaia DR1 TGAS main sequence stars". Monthly Notices of the Royal Astronomical Society. 472 (4): 3805–3820. arXiv:1709.01160. Bibcode:2017MNRAS.472.3805G. doi:10.1093/mnras/stx2219. eISSN 1365-2966. ISSN 0035-8711. S2CID 118879856.
  14. Pertersson, J. H. (1927). "Distribution of stars in Carrington zone". Meddelanden fran Astronomiska Observatorium Uppsala. 29: 1. Bibcode:1927MeUpp..29....1P.
  15. Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  16. Gaia Collaboration (2022). "VizieR Online Data Catalog: Gaia DR3 Part 3. Non-single stars (Gaia Collaboration, 2022)". Vizier Online Data Catalog. Bibcode:2022yCat.1357....0G.
  17. Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (December 2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466–3471. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. ISSN 0004-6256. S2CID 119533755.
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