| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Leo |
| Right ascension | 11h36m 56.92983s[1] |
| Declination | +00° 49′ 25.8758″[1] |
| Apparent magnitude (V) | 4.33[2] |
| Characteristics | |
| Spectral type | G9 III[3] |
| U−B color index | +0.76[2] |
| B−V color index | +1.00[2] |
| Astrometry | |
| Radial velocity (Rv) | 1.79±0.16[4] km/s |
| Proper motion (μ) | RA: +1.76[1] mas/yr Dec.: +43.37[1] mas/yr |
| Parallax (π) | 17.97 ± 0.22 mas[1] |
| Distance | 182 ± 2 ly (55.6 ± 0.7 pc) |
| Absolute magnitude (MV) | 0.59[5] |
| Details | |
| Mass | 2.58[5] M☉ |
| Radius | 11[4] R☉ |
| Luminosity | 56[4] L☉ |
| Surface gravity (log g) | 2.7[4] cgs |
| Temperature | 4,842[4] K |
| Metallicity [Fe/H] | –0.34[4] dex |
| Rotational velocity (v sin i) | 0.0[4] km/s |
| Age | 4.12±2.08[6] Gyr |
| Other designations | |
υ Leo, 91 Leo, BD−00°2458, FK5 437, HD 100920, HIP 56647, HR 4471, SAO 138298[7] | |
| Database references | |
| SIMBAD | data |
Upsilon Leonis (υ Leo) is a star in the zodiac constellationofLeo. It is visible to the naked eye with an apparent visual magnitude of 4.33.[2] The distance to this star, as determined using parallax measurements,[1] is about 182 light years. At that distance, the visual magnitude of the star is diminished by an estimated extinction factor of 0m.02 because of interstellar dust.[5]
With an age of around 4 billion years, this star has evolved into a G-type giant star with a stellar classification of G9 III.[3] It has 2.6 times the Sun's mass,[5] but has expanded to 11 times the solar radius and shines with 56 times the luminosity of the Sun at an effective temperature of 4,842 K.[4] The rate of rotation is too small to be measured, with a projected rotational velocity of 0.0 km/s.[4] The chemical abundance of elements other than hydrogen and helium, what astronomers term the star's metallicity, is less than half that in the Sun.[4] It is most likely a member of the galactic thin disk population.[6]
In 2021, a gas giant planet was detected by radial velocity method.[8]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >0.51+0.06 −0.26 MJ |
1.18+0.11 −0.32 |
385.2+2.8 −1.3 |
0.320+0.134 −0.218 |
— | — |
|
| |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| |||||||||||||
| Stars |
| ||||||||||||
| |||||||||||||
| Galaxies |
| ||||||||||||
