21 Leonis Minoris

21 Leonis Minoris is a star in the constellation of Leo Minor. With an apparent magnitude of about 4.5, the star is faintly visible to the naked eye (see Bortle scale). Parallax estimates made by the Hipparcos spacecraft put it at a fairly close distance of about 92.1 light years (28.2 parsecs) away from the Earth.[1] It is considered a member of the Sirius supercluster.[6]

21 Leonis Minoris
Observation data
Epoch J2000      Equinox J2000
Constellation Leo Minor
Right ascension 10h 07m 25.76296s[1]
Declination +35° 14′ 40.8965″[1]
Apparent magnitude (V) 4.47 - 4.52[2]
Characteristics
Spectral type A7V[3]
U−B color index +0.08[4]
B−V color index +0.18[4]
Variable type δ Sct[2]
Astrometry
Radial velocity (Rv)−11.40 ± 0.9[5] km/s
Proper motion (μ) RA: 52.90[1] mas/yr
Dec.: 0.62[1] mas/yr
Parallax (π)35.41 ± 0.18[1] mas
Distance92.1 ± 0.5 ly
(28.2 ± 0.1 pc)
Absolute magnitude (MV)+2.43[6]
Details
Mass1.75[7] M☉
Radius1.75[7] R☉
Luminosity9.91[7] L☉
Surface gravity (log g)4.07[8] cgs
Temperature7839[8] K
Metallicity [Fe/H]0.03±0.08[7] dex
Rotational velocity (v sin i)155[9] km/s
Age390[9] Myr
750[7] Myr
Other designations
21 LMi, BD+35°2110, GJ 378.3, 9314, HD 87696, HIP 49593, HR 3974, SAO 61874[10]
Database references
SIMBADdata

21 Leonis Minoris rotates fairly fast for a star; its projected rotational velocity is estimated to 155 km/s[9] so it must be rotating at least that fast. It has been listed as a fast-rotating spectral standard star for the spectral type of A7V, as opposed to the slow-rotating standard star 2 Hydrae.[11] It is also a Delta Scuti variable, and its apparent magnitude varies from 4.47 to 4.52.[2]

21 Leonis Minoris has an infrared excess, suggesting a debris disk around it.[9] The black body fit has a temperature of 60 K with an orbital radius of 62 AU.[7]

References
  1. van Leeuwen, F.; et al. (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.
  2. Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1. Bibcode:2009yCat....1.2025S.
  3. Johnson, H. L.; Morgan, W. W. (1953). "Fundamental stellar photometry for standards of spectral type on the revised system of the Yerkes spectral atlas". The Astrophysical Journal. 117: 313. Bibcode:1953ApJ...117..313J. doi:10.1086/145697.
  4. Johnson, H. L. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99. Bibcode:1966CoLPL...4...99J.
  5. 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. Eggen, Olin J. (August 1998), "The Sirius Supercluster and Missing Mass near the Sun", The Astronomical Journal, 116 (2): 782–788, Bibcode:1998AJ....116..782E, doi:10.1086/300465.
  7. Gáspár, András; et al. (2016), "The Correlation between Metallicity and Debris Disk Mass", The Astrophysical Journal, 826 (2): 171, arXiv:1604.07403, Bibcode:2016ApJ...826..171G, doi:10.3847/0004-637X/826/2/171, S2CID 119241004.
  8. Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Robinson, P. E. (2003). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I". The Astronomical Journal. 126 (4): 2048. arXiv:astro-ph/0308182. Bibcode:2003AJ....126.2048G. doi:10.1086/378365. S2CID 119417105.
  9. Rieke, G. H.; Su, K. Y. L.; Stansberry, J. A.; Trilling, D.; Bryden, G.; Muzerolle, J.; White, B.; Gorlova, N.; Young, E. T.; Beichman, C. A.; Stapelfeldt, K. R.; Hines, D. C. (2005). "Decay of Planetary Debris Disks". The Astrophysical Journal. 620 (2): 1010. Bibcode:2005ApJ...620.1010R. CiteSeerX 10.1.1.579.8956. doi:10.1086/426937.
  10. "* 21 LMi". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 22 March 2017.
  11. Gray, R. O.; Garrison, R. F. (1989). "The late A-type stars - Refined MK classification, confrontation with Stromgren photometry, and the effects of rotation". The Astrophysical Journal Supplement Series. 70: 623. Bibcode:1989ApJS...70..623G. doi:10.1086/191349.
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