Alight curve for Rho Leonis, plotted from Hipparcos data[11]
This is an enormous star with about 20 times theSun's mass (M☉) and 28 times theSun's radius.[6] Itsspectrum matches astellar classification of B1 Iab,[3] with the 'Iab'luminosity class indicating that it is in thesupergiant stage of itsevolution. Rho Leonis is radiating about 150,000 times theSun's luminosity at aneffective temperature of 21,700 K,[6] giving it the blue-white hue typical of a B-type star. A strongstellar wind is expelling mass from the outer envelope at a rate of3.5×10−7M☉ per year, or the equivalent of 1M☉ every 2.8 million years.[12] The rotation rate is probably about once per 7 days, with an upper limit of 47 days.[8]
Rho Leonis is classified as arunaway star, which means it has apeculiar velocity of at least 30 km s−1 relative to the surrounding stars. It hasradial velocity of42 km s−1 away from theSun and aproper motion that is carrying it about 1.56Astronomical Units per year, equivalent to 7 km s−1,[13] in a transverse direction. The star is situated about 2,300 light-years (710 parsecs) above thegalactic plane.[14]
Rho Leo is 0.15 degree north of the ecliptic, so it can be occulted by the moon. Unusual light variation during these occultations has been explained as the result of a possible close companion. The companion would be just over one magnitude fainter and separated by 0.01 arcsec.[15] The companion has not been detected by any other means although it should be easily detected with modern observations.[16]
This star has the traditional Chinese name Shaomin (少民); it andο Leonis (Taimin, 太民) were the two southernmost stars of the Xuanyuan (轩辕) constellation. TheIAU Working Group on Star Names approved the name Shaomin for ρ Leonis on 18 July 2024 and it is now so entered in the IAU Catalog of Star Names; ο Leonis has the IAU-approved name Subra.[9]
^abSamus, 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....102025S.
^Radick, R. R.; Africano, J. L.; Flores, M. R.; Klimke, D. A.; Tyson, E. T. (1982). "Cloudcroft occultation summary. II - April 1980-December 1981".The Astronomical Journal.87: 1874.Bibcode:1982AJ.....87.1874R.doi:10.1086/113277.ISSN0004-6256.
