Gamma Leonis
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Leo |
| Right ascension | 10h 19m 58.35056s |
| Declination | +19° 50′ 29.3468″ |
| Apparent magnitude (V) | 2.08 (2.37/3.64) |
| Characteristics | |
| Evolutionary stage | Red clump |
| Spectral type | K0III + G7III |
| U−B color index | +1.00 |
| B−V color index | +1.15 |
| Variable type | Unknown-type variable (B) |
| Astrometry | |
| Radial velocity (Rv) | −36.24±0.18 km/s |
| Proper motion (μ) | RA: +304.30 mas/yr Dec.: −154.28 mas/yr |
| Parallax (π) | 25.07±0.52 mas |
| Distance | 130 ± 3 ly (39.9 ± 0.8 pc) |
| Absolute magnitude (MV) | −0.27/+0.98 |
| Orbit | |
| Period (P) | 554±27 yr |
| Semi-major axis (a) | 3.1±0.1″ |
| Eccentricity (e) | 0.93±0.02 |
| Inclination (i) | 41±5° |
| Longitude of the node (Ω) | 143.4° |
| Periastron epoch (T) | 1671.3 |
| Details | |
| γ Leo A | |
| Mass | 1.66±0.14 M☉ |
| Radius | 26.08±0.79 – 31.88±1.61 R☉ |
| Luminosity | 250 L☉ |
| Surface gravity (log g) | 1.8±0.04 cgs |
| Temperature | 4,457±63 K |
| Metallicity [Fe/H] | −0.41±0.03 dex |
| Rotational velocity (v sin i) | 1.41 km/s |
| Age | 1.75±0.43 Gyr |
| γ Leo B | |
| Mass | 1.55±0.08 M☉ |
| Radius | 10.55±0.29 R☉ |
| Luminosity | 63.1 L☉ |
| Surface gravity (log g) | 2.56±0.04 cgs |
| Temperature | 4,969±15 K |
| Metallicity [Fe/H] | –0.38 ± 0.02 dex |
| Rotational velocity (v sin i) | 1.62 km/s |
| Age | 2.12±0.33 Gyr |
| Other designations | |
| Algieba, γ Leonis, 41 Leo, NSV 4823, BD+20°2467, HIP 50583, WDS 10200+1950, LTT 12764/12765 | |
| γ Leo A: γ1 Leonis, HD 89484, HR 4057, SAO 81298 | |
| γ Leo B: γ2 Leonis, HD 89485, HR 4058, SAO 81299 | |
| Position (relative to A) | |
| Component | B |
| Epoch of observation | 1820 – 2022 |
| Angular distance | 3.7" (1820), 4.7" (2022)″ |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
Gamma Leonis (γ Leonis, abbreviated Gamma Leo, γ Leo), also named Algieba /ælˈdʒiːbə/, is a binary star system in the constellation of Leo, made up of two red giants. The primary star is orbited by one known exoplanet.