Chi Leonis

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]

χ Leonis

Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
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 mas[1]
Distance	94.6 ± 0.5 ly (29.0 ± 0.2 pc)
Absolute magnitude (MV)	+2.31[6]
Details
Mass	1.62[7] M☉
Radius	1.99[8] R☉
Luminosity	9.9[6] L☉
Surface gravity (log g)	4.02[7] cgs
Temperature	7022±80[7] K
Metallicity [Fe/H]	+0.03[7] dex
Rotational velocity (v sin i)	25±1[4] km/s
Age	1.40[7] Gyr
Other designations
χ Leo, 63 Leo, BD+08°2455, FK5 418, HD 96097, HIP 54182, HR 4310, SAO 118648[9]
Database references
SIMBAD	data

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