Surface temperature 4,000 K Radius 41.76 million km (60 R☉) | Mass 3.978 × 10^30 kg (2 M☉) Magnitude 4.32 Apparent magnitude (V) 4.32 | |
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Similar Zeta Leonis, Gamma Leonis, Delta Leonis, Denebola, Nu Ursae Majoris | ||
Lambda Leonis (λ Leo, λ Leonis) is a star in the constellation Leo. It has the traditional name Alterf, from the Arabic الطرف aṭ-ṭarf "the view (of the lion)". This star, along with ξ Cnc, were the Persian Nahn, "the Nose", and the Coptic Piautos, "the Eye", both lunar asterisms. 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.
This is a K-type giant star with a stellar classification of K4.5 III. It is a suspected variable star with a reported magnitude range of 4.28−4.34. The interferometry-measured angular diameter of this star, after correcting for limb darkening, is 7000412000000000000♠4.12±0.05 mas, which, at its estimated distance, equates to a physical radius of nearly 45 times the radius of the Sun. It shines with around 472 times the luminosity of the Sun, from an outer atmosphere that has an effective temperature of 3,900 K.