Lambda Leonis

Lambda Leonis
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Leo
Right ascension 09h 31m 43.22754s[1]
Declination +22° 58′ 04.6904″[1]
Apparent magnitude (V) 4.32[2]
Characteristics
Spectral type K4.5 III[3]
U−B color index +1.82[2]
B−V color index +1.54[2]
Astrometry
Radial velocity (Rv)24.27±0.19[4] km/s
Proper motion (μ) RA: −20.17[1] mas/yr
Dec.: −39.47[1] mas/yr
Parallax (π)9.91 ± 0.18 mas[1]
Distance329 ± 6 ly
(101 ± 2 pc)
Absolute magnitude (MV)−0.70[5]
Details[6]
Mass1.29±0.18 M☉
Radius44.93+0.85
−0.87 R☉
Luminosity541.4±33.5 L☉
Surface gravity (log g)1.70 cgs
Temperature4,152±53 K
Metallicity [Fe/H]−0.21 dex
Rotational velocity (v sin i)8[7] km/s
Age3.62±1.37 Gyr
Other designations
Alterf, λ Leo, 4 Leo, BD+23°2107, HD 82308, HIP 46750, HR 3773, SAO 80885[8]
Database references
SIMBADdata

Lambda Leonis (λ Leonis, abbreviated Lam Leo, λ Leo), formally named Alterf /ælˈtərf/,[9][10] 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[2] 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.[4]

  1. ^ a b c d e Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Mermilliod1986 was invoked but never defined (see the help page).
  3. ^ Cite error: The named reference Keenan1989 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Famaey2005 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Baines2018 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Bernacca1970 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  9. ^ Kunitzsch, Paul; Smart, Tim (2006). A Dictionary of Modern star Names: A Short Guide to 254 Star Names and Their Derivations (2nd rev. ed.). Cambridge, Massachusetts: Sky Pub. ISBN 978-1-931559-44-7.
  10. ^ "Naming Stars". IAU.org. Retrieved 16 December 2017.