54 Leonis

54 Leonis
Observation data
Epoch J2000.0      Equinox
Constellation Leo
54 Leo A
Right ascension 10h 55m 36.80266s[1]
Declination +24° 44′ 59.0440″[1]
Apparent magnitude (V) 4.477[2]
54 Leo B
Right ascension 10h 55m 37.24836s[3]
Declination +24° 44′ 56.5478″[3]
Apparent magnitude (V) 6.29[4]
Characteristics
54 Leo A
Spectral type A0 V[5]
B−V color index +0.001[5]
54 Leo B
Spectral type A2 Vn[5]
B−V color index +0.07[4]
Astrometry
54 Leo A
Radial velocity (Rv)−0.49±0.98[6] km/s
Proper motion (μ) RA: −78.057[1] mas/yr
Dec.: −16.520[1] mas/yr
Parallax (π)9.8275 ± 0.3537 mas[1]
Distance330 ± 10 ly
(102 ± 4 pc)
Absolute magnitude (MV)–0.29[7]
54 Leo B
Radial velocity (Rv)1.30±0.92[6] km/s
Proper motion (μ) RA: −75.374[3] mas/yr
Dec.: −18.595[3] mas/yr
Parallax (π)10.1748 ± 0.0569 mas[3]
Distance321 ± 2 ly
(98.3 ± 0.5 pc)
Details
54 Leo A
Mass2.4+0.44
−0.36[8] M☉
Radius2.88[9] R☉
Surface gravity (log g)3.5±0.25[8] cgs
Temperature9000±500[8] K
Rotational velocity (v sin i)185[10] km/s
Age411+137
−168[8] Myr
54 Leo B
Radius2.59[9] R☉
Rotational velocity (v sin i)250±20[9] km/s
Other designations
54 Leo, BD+25 2314, CCDM J10556+2445, HIP 53417, Struve 1487[11]
54 Leo A: HD 94601, HR 4259, SAO 81583
54 Leo B: HD 94602, HR 4260, SAO 81584
Database references
SIMBADdata

54 Leonis is a binary star[12] system in the zodiac constellation of Leo, located around 321[3] light years from the Sun. It is visible to the naked eye as a faint, white-hued star with a combined apparent visual magnitude of 4.30.[13] As of 2017, the pair had an angular separation of 6.60″ along a position angle of 113°.[14] They have a physical separation of around 533 AU (79,700 Gm).[9]

The magnitude 4.477[2] primary, designated component A, is an A-type main-sequence star with a stellar classification of A0 V,[5] which indicates it is generating energy through hydrogen fusion at its core. It has a high rate of spin, showing a projected rotational velocity of 185 km/s. This is giving the star an oblate shape with an equatorial bulge that is an estimated 8% larger than the polar radius.[10] The star is roughly 411[8] million years old with 2.4[8] times the mass of the Sun and about 2.88[9] times the Sun's radius.

The fainter magnitude 6.29[4] secondary, component B, is a smaller A-type main-sequence star with a class of A2 Vn.[5] The 'n' suffix indicates wide "nebulous" lines due to rapid rotation. It is spinning with an even higher projected rotational velocity of 250[9] km/s. The star has about 2.59[9] times the Sun's radius.

Asteroid 729 Watsonia occulted HIP 53417 on March 3, 2013 at 01:48.[15]

  1. ^ a b c d e Cite error: The named reference gaia_dr2_A was invoked but never defined (see the help page).
  2. ^ a b Cite error: The named reference tycho2 was invoked but never defined (see the help page).
  3. ^ a b c d e f Cite error: The named reference gaia_dr2_B was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference tycho was invoked but never defined (see the help page).
  5. ^ a b c d e Cite error: The named reference Cowley1969 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Becker2015 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Pizzolato2000 was invoked but never defined (see the help page).
  8. ^ a b c d e f Cite error: The named reference Gullikson2016 was invoked but never defined (see the help page).
  9. ^ a b c d e f g Cite error: The named reference Howe2009 was invoked but never defined (see the help page).
  10. ^ a b Cite error: The named reference belle2012 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Anderson2012 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference wds2006 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Ricci2012 was invoked but never defined (see the help page).