Lambda Leonis
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Leo |
| Right ascension | 09h 31m 43.22754s |
| Declination | +22° 58′ 04.6904″ |
| Apparent magnitude (V) | 4.32 |
| Characteristics | |
| Spectral type | K4.5 III |
| U−B color index | +1.82 |
| B−V color index | +1.54 |
| Astrometry | |
| Radial velocity (Rv) | 24.27±0.19 km/s |
| Proper motion (μ) | RA: −20.17 mas/yr Dec.: −39.47 mas/yr |
| Parallax (π) | 9.91±0.18 mas |
| Distance | 329 ± 6 ly (101 ± 2 pc) |
| Absolute magnitude (MV) | −0.70 |
| Details | |
| Mass | 1.29±0.18 M☉ |
| Radius | 44.93+0.85 −0.87 R☉ |
| Luminosity | 541.4±33.5 L☉ |
| Surface gravity (log g) | 1.70 cgs |
| Temperature | 4,152±53 K |
| Metallicity [Fe/H] | −0.21 dex |
| Rotational velocity (v sin i) | 8 km/s |
| Age | 3.62±1.37 Gyr |
| Other designations | |
| Alterf, λ Leo, 4 Leo, BD+23°2107, HD 82308, HIP 46750, HR 3773, SAO 80885 | |
| Database references | |
| SIMBAD | data |
Lambda Leonis (λ Leonis, abbreviated Lam Leo, λ Leo), formally named Alterf /ælˈtərf/, is a star in the constellation of Leo. The star is bright enough to be seen with the naked eye, having an apparent visual magnitude of 4.32 Based upon an annual parallax shift of 0.00991 arcseconds, it is located about 329 light-years from the Sun. At that distance, the visual magnitude of the star is reduced by an interstellar absorption factor of 0.06 because of extinction.