This is an enormous star with about 21 times the
Sun's mass (
M☉)[16] and 37 times the
Sun's radius.[8] Its
spectrum matches a
stellar classification of B1 Iab,[3] with the 'Iab'
luminosity class indicating that it is in the
supergiant stage of its
evolution. Rho Leonis is radiating about 45,000 times the
Sun's luminosity at an
effective temperature of 22,000 K,[9] giving it the blue-white hue typical of a B-type star. A strong
stellar wind is expelling mass from the outer envelope at a rate of 3.5×10−7M☉ per year, or the equivalent of 1 M☉ every 2.8 million years.[8] The rotation rate is probably about once per 7 days, with an upper limit of 47 days.[11]
Rho Leonis is classified as a
runaway star, which means it has a
peculiar velocity of at least 30 km s−1 relative to the surrounding stars. It has
radial velocity of 42 km s−1 away from the
Sun and a
proper motion that is carrying it about 1.56
Astronomical Units per year, equivalent to 7 km s−1,[17] in a transverse direction. The star is situated about 2,300 light-years (710 parsecs) above the
galactic plane.[18]
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.[19] The companion has not been detected by any other means although it should be easily detected with modern observations.[20]
^
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.
^
abcGutierrez-Moreno, Adelina; et al. (1966). "A System of photometric standards". Publ. Dept. Astron. Univ. Chile. 1: 1–17.
Bibcode:
1966PDAUC...1....1G.
^Wilson, Ralph Elmer (1953). "General Catalogue of Stellar Radial Velocities". Washington.
Bibcode:
1953GCRV..C......0W.
^"Light Curve". Hipparcos ESA. ESA. Retrieved 17 February 2022.
^Conlon, E. S.; et al. (September 1990). "The runaway nature of distant early-type stars in the galactic halo". Astronomy and Astrophysics. 236 (2): 357–361.
Bibcode:
1990A&A...236..357C.
^An Astronomical Unit (AU) is 1.5 × 108 km, while a year is 3.2 × 107 seconds. Thus, 1.56 AU/year = (1.56 AU/yr) × (1.5 × 108 km/AU) / (3.2 × 107 s/yr) = 7 km/s.
^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.