Sigma Leonis

Sigma Leonis
Observation data
Epoch J2000      Equinox J2000
Constellation Leo
Right ascension 11h 21m 08.1943s[1]
Declination +06° 01′ 45.558″[1]
Apparent magnitude (V) 4.046[2]
Characteristics
Spectral type B9.5 Vs[3]
U−B color index –0.12[4]
B−V color index –0.06[4]
Astrometry
Radial velocity (Rv)–5.3[5] km/s
Proper motion (μ) RA: –91.76[1] mas/yr
Dec.: –12.83[1] mas/yr
Parallax (π)15.24 ± 0.81 mas[1]
Distance210 ± 10 ly
(66 ± 3 pc)
Absolute magnitude (MV)−0.10[6]
Details
Mass2.76[7] M☉
Radius3.3[8] R☉
Luminosity133[6] L☉
Surface gravity (log g)3.83±0.03[9] cgs
Temperature10,250[8] K
Metallicity [Fe/H]+0.0[8] dex
Rotational velocity (v sin i)70[10] km/s
Age293[7] Myr
Other designations
σ Leo, 77 Leo, BD−06°2437, FK5 427, HD 98664, HIP 55434, HR 4386, SAO 118804[11]
Database references
SIMBADdata

Sigma Leonis, Latinized from σ Leonis, is a blue-white hued star in the zodiac constellation Leo that is visible to the naked eye with an apparent visual magnitude of 4.0.[2] Its annual parallax shift of 15.24 mas as seen from Earth implies a distance around 210 light years from the Sun. It is moving closer to the Sun with a radial velocity of –5 km/s.[5]

Chini et al. (2012) list this as a single-lined spectroscopic binary system.[3] The visible component has a stellar classification of B9.5 Vs,[3] indicating it is a B-type main-sequence star. It is a suspected magnetic Ap star that shows an abundance anomaly with the element silicon.[12] Sigma Leonis has an estimated 2.76[7] times the mass of the Sun and 3.3[8] times the Sun's radius. It is about 293[7] million years old with a projected rotational velocity of 70 km/s.[10] The star is radiating 133[6] times the Sun's luminosity from its photosphere at an effective temperature of 10,250 K.[8]

  1. ^ a b c d e Cite error: The named reference aaa323_L49 was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference Cousins1984 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Chini2012 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference clpl4 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference gcsrv53 was invoked but never defined (see the help page).
  6. ^ a b c Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  7. ^ a b c d Cite error: The named reference David2015 was invoked but never defined (see the help page).
  8. ^ a b c d e Cite error: The named reference mnras385_1_481 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference aj129_3_1642 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference csrv was invoked but never defined (see the help page).
  11. ^ "sig Leo -- Star". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2010-06-23.
  12. ^ Cite error: The named reference Wraight2012 was invoked but never defined (see the help page).