Beta Equulei

Beta Equulei, Latinized from β Equulei, is the Bayer designation for a solitary[9] star in the northern constellation of Equuleus. It is faintly visible to the naked eye with an apparent visual magnitude of 5.16.[2] The annual parallax shift is 11.27 mas,[1] indicating a separation of around 289 light years from the Sun. It is drifting closer with a radial velocity of −11 km/s.[6]

Beta Equulei
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Equuleus
Right ascension 21h 22m 53.61365s[1]
Declination +06° 48′ 40.1125″[1]
Apparent magnitude (V) 5.16[2]
Characteristics
Evolutionary stage Main sequence[3]
Spectral type A3 V[4]
U−B color index +0.10[5]
B−V color index +0.064±0.003[2]
Astrometry
Radial velocity (Rv)−11.1±0.8[6] km/s
Proper motion (μ) RA: +53.685[1] mas/yr
Dec.: +10.136[1] mas/yr
Parallax (π)11.2696 ± 0.2608[1] mas
Distance289 ± 7 ly
(89 ± 2 pc)
Absolute magnitude (MV)+0.13[2]
Details
Mass2.74±0.04[3] M☉
Radius4.02[7] R☉
Luminosity78.3[2] L☉
Temperature9,000[7] K
Rotational velocity (v sin i)58.0±0.7[4] km/s
Age600[7] Myr
Other designations
β Equ, 10 Equulei, BD+06°4811, HD 203562, HIP 105570, HR 8178, SAO 126749, WDS 21229+0649A[8]
Database references
SIMBADdata

This is an ordinary A-type main sequence star with a stellar classification of A3 V.[4] It has 2.7 times the mass of the Sun[3] and about four[7] times the Sun's radius. The star is around 600[7] million years old – 93%[3] of the way through it's main sequence lifetime – and is spinning with a projected rotational velocity of 58 km/s.[4] It is radiating 78[2] times the luminosity of the Sun from its photosphere at an effective temperature of about 9,000 K.[7] The star emits an infrared excess indicating the presence of a dusty debris disk. The mean temperature of the dust is 85 K, indicating the semimajor axis of its orbit is 104 AU.[7]

β Equulei has four optical companions. They are not physically associated with the star described above.[10]

References
  1. 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.
  2. 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.
  3. Zorec, J.; Royer, F. (2012), "Rotational velocities of A-type stars. IV. Evolution of rotational velocities", Astronomy & Astrophysics, 537: A120, arXiv:1201.2052, Bibcode:2012A&A...537A.120Z, doi:10.1051/0004-6361/201117691, S2CID 55586789.
  4. Díaz, C. G.; et al. (July 2011), "Accurate stellar rotational velocities using the Fourier transform of the cross correlation maximum", Astronomy & Astrophysics, 531: A143, arXiv:1012.4858, Bibcode:2011A&A...531A.143D, doi:10.1051/0004-6361/201016386, S2CID 119286673.
  5. Mermilliod, J.-C. (1986), "Compilation of Eggen's UBV data, transformed to UBV (unpublished)", Catalogue of Eggen's UBV Data, SIMBAD, Bibcode:1986EgUBV........0M.
  6. Gontcharov, G. A. (November 2006), "Pulkovo Compilation of Radial Velocities for 35,495 Hipparcos stars in a common system", Astronomy Letters, 32 (11): 759–771, arXiv:1606.08053, Bibcode:2006AstL...32..759G, doi:10.1134/S1063773706110065, S2CID 119231169.
  7. Rhee, Joseph H.; et al. (May 2007), "Characterization of Dusty Debris Disks: The IRAS and Hipparcos Catalogs", The Astrophysical Journal, 660 (2): 1556–1571, arXiv:astro-ph/0609555, Bibcode:2007ApJ...660.1556R, doi:10.1086/509912, S2CID 11879505.
  8. "bet Equ". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2017-02-17.
  9. 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.
  10. Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466–3471, Bibcode:2001AJ....122.3466M, doi:10.1086/323920.
  • Kaler, James B. (December 18, 2009), "Beta Equulei", Stars, University of Illinois.
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