| Observation data Epoch J2000.0 Equinox | |
|---|---|
| Constellation | Leo |
| 54 Leo A | |
| Right ascension | 10 55 36.80266 |
| Declination | +24° 44′ 59.0440″ |
| Apparent magnitude (V) | 4.477 |
| 54 Leo B | |
| Right ascension | 10 55 37.24836 |
| Declination | +24° 44′ 56.5478″ |
| Apparent magnitude (V) | 6.29 |
| Characteristics | |
| 54 Leo A | |
| Spectral type | A0 V |
| B−V color index | +0.001 |
| 54 Leo B | |
| Spectral type | A2 Vn |
| B−V color index | +0.07 |
| Astrometry | |
| 54 Leo A | |
| Radial velocity (Rv) | −0.49±0.98 km/s |
| Proper motion (μ) | RA: −78.057 mas/yr Dec.: −16.520 mas/yr |
| Parallax (π) | 9.8275 ± 0.3537 mas |
| Distance | 330 ± 10 ly (102 ± 4 pc) |
| Absolute magnitude (MV) | –0.29 |
| 54 Leo B | |
| Radial velocity (Rv) | 1.30±0.92 km/s |
| Proper motion (μ) | RA: −75.374 mas/yr Dec.: −18.595 mas/yr |
| Parallax (π) | 10.1748 ± 0.0569 mas |
| Distance | 321 ± 2 ly (98.3 ± 0.5 pc) |
| Details | |
| 54 Leo A | |
| Mass | 2.4+0.44 −0.36 M☉ |
| Radius | 2.88 R☉ |
| Surface gravity (log g) | 3.5±0.25 cgs |
| Temperature | 9000±500 K |
| Rotational velocity (v sin i) | 185 km/s |
| Age | 411+137 −168 Myr |
| 54 Leo B | |
| Radius | 2.59 R☉ |
| Rotational velocity (v sin i) | 250±20 km/s |
| Other designations | |
| 54 Leo, BD+25 2314, CCDM J10556+2445, HIP 53417, Struve 1487 | |
| 54 Leo A: HD 94601, HR 4259, SAO 81583 | |
| 54 Leo B: HD 94602, HR 4260, SAO 81584 | |
| Database references | |
| SIMBAD | data |
54 Leonis is a binary star system in the zodiac constellation of Leo, located around 321 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. As of 2017, the pair had an angular separation of 6.60″ along a position angle of 113°. They have a physical separation of around 533 AU (79,700 Gm).
The magnitude 4.477 primary, designated component A, is an A-type main-sequence star with a stellar classification of A0 V, 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. The star is roughly 411 million years old with 2.4 times the mass of the Sun and about 2.88 times the Sun's radius.
The fainter magnitude 6.29 secondary, component B, is a smaller A-type main-sequence star with a class of A2 Vn. The 'n' suffix indicates wide "nebulous" lines due to rapid rotation. It is spinning with an even higher projected rotational velocity of 250 km/s. The star has about 2.59 times the Sun's radius.
Asteroid 729 Watsonia occulted HIP 53417 on March 3, 2013 at 01:48.
References
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ Høg, E.; et al. (2000), "The Tycho-2 catalogue of the 2.5 million brightest stars", Astronomy and Astrophysics, 355: L27, Bibcode:2000A&A...355L..27H, doi:10.1888/0333750888/2862.
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ Fabricius, C.; et al. (2002), "The Tycho double star catalogue", Astronomy and Astrophysics, 384: 180–189, Bibcode:2002A&A...384..180F, doi:10.1051/0004-6361:20011822
- ^ Cowley, A.; et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal, 74: 375–406, Bibcode:1969AJ.....74..375C, doi:10.1086/110819.
- ^ Becker, Juliette C.; et al. (April 2015), "Extracting Radial Velocities of A- and B-type Stars from Echelle Spectrograph Calibration Spectra", The Astrophysical Journal Supplement Series, 217 (2): 13, arXiv:1503.03874, Bibcode:2015ApJS..217...29B, doi:10.1088/0067-0049/217/2/29, S2CID 33968873, 29.
- Pizzolato, N.; Maggio, A.; Sciortino, S. (September 2000), "Evolution of X-ray activity of 1-3 Msun late-type stars in early post-main-sequence phases", Astronomy and Astrophysics, 361: 614–628, Bibcode:2000A&A...361..614P
- ^ Gullikson, Kevin; et al. (2016), "The Close Companion Mass-ratio Distribution of Intermediate-mass Stars", The Astronomical Journal, 152 (2): 40, arXiv:1604.06456, Bibcode:2016AJ....152...40G, doi:10.3847/0004-6256/152/2/40, S2CID 119179065.
- ^ Howe, K. S.; Clarke, C. J. (January 2009), "An analysis of v sin (i) correlations in early-type binaries", Monthly Notices of the Royal Astronomical Society, 392 (1): 448–454, Bibcode:2009MNRAS.392..448H, doi:10.1111/j.1365-2966.2008.14073.x
- ^ Belle, G. T. (2012), "Interferometric observations of rapidly rotating stars", The Astronomy and Astrophysics Review, 20 (1): 51, arXiv:1204.2572, Bibcode:2012A&ARv..20...51V, doi:10.1007/s00159-012-0051-2, S2CID 119273474.
- "54 Leo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-02-05.
- Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
- Mason, Brian D.; et al. (December 2001), "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog", The Astronomical Journal, 122 (6), U. S. Naval Observatory, Washington D.C.: 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
- Pier Paolo Ricci (29 November 2012). Almanacco astronomico 2013 Astronomical almanac 2013. Lulu.com. pp. 322–. ISBN 978-1-291-21157-3.
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