BP Boötis

BP Boötis
Location of BP Boötis (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Boötes
Right ascension 15h 42m 50.760818s[1]
Declination +52° 21′ 39.24441″[1]
Apparent magnitude (V) 5.48[2]
Characteristics
Spectral type A0 Vp Si Cr[3]
B−V color index −0.042±0.004[2]
Variable type α2 CVn[4]
Astrometry
Radial velocity (Rv)−16.1±2.8[2] km/s
Proper motion (μ) RA: −66.214[1] mas/yr
Dec.: +29.308[1] mas/yr
Parallax (π)10.92 ± 0.18 mas[1]
Distance299 ± 5 ly
(92 ± 2 pc)
Absolute magnitude (MV)+0.48[5]
Details[5]
Mass2.58±0.07 M☉
Radius2.7±0.2 R☉
Luminosity65 L☉
Surface gravity (log g)3.99±0.07 cgs
Temperature9,954 K
Rotation1.29557 days
Rotational velocity (v sin i)69[6] km/s
Age170[6] Myr
Other designations
BP Boo, BD+52°1898, FK5 3247, GC 21154, HD 140728, HIP 76957, HR 5857, SAO 29628[7]
Database references
SIMBADdata
Light curve for BP Boötis, plotted from TESSdata[8]

BP Boötis is a solitary[9] variable star in the northern constellation of Boötes, near the northern constellation border with Draco. It is visible to the naked eye as a dim, white-hued star with an apparent visual magnitude that fluctuates around 5.48.[2] The star is located 299 light years away from the Sun based on parallax, but is drifting closer with a radial velocity of −16 km/s.[2]

The star, often called HD 140728 before it was known to be variable, was transferred from Boötes to Quadrans Muralis. Later, when the International Astronomical Union officially recognised constellations, Quadrans Muralis became obsolete, so this star was moved back to Boötes.[10] In 1962, William Wehlau announced that the star's brightness varied, based on observations made from 1958 through 1960.[11]

This is an Ap star with a stellar classification of A0 Vp Si Cr,[3] showing abundance anomalies of silicon and chromium. It is an Alpha2 Canum Venaticorum variable that varies in brightness by 0.02 magnitude over a period of 1.3 days.[4][12] The distribution of silicon across the surface appears to be associated with the magnetic field of the star, with depleted regions appearing around the magnetic poles.[13]

BP Boötis is 170[6] million years old with a projected rotational velocity of 69 km/s,[6] having a rotation period of 1.29557 days. It has 2.6 times the mass of the Sun and 2.7 times the Sun's radius. The star is radiating 65 times the luminosity of the Sun from its photosphere at an effective temperature of 9,954 K.[5]

References

  1. ^ a b c d e 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. ^ a b c d e 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. ^ a b Abt, Helmut A.; Morrell, Nidia I. (1995), "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars", Astrophysical Journal Supplement Series, 99: 135, Bibcode:1995ApJS...99..135A, doi:10.1086/192182
  4. ^ a b Samus', N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
  5. ^ a b c North, P. (June 1998), "Do SI stars undergo any rotational braking?", Astronomy and Astrophysics, 334: 181–187, arXiv:astro-ph/9802286, Bibcode:1998A&A...334..181N.
  6. ^ a b c d David, Trevor J.; Hillenbrand, Lynne A. (2015), "The Ages of Early-Type Stars: Strömgren Photometric Methods Calibrated, Validated, Tested, and Applied to Hosts and Prospective Hosts of Directly Imaged Exoplanets", The Astrophysical Journal, 804 (2): 146, arXiv:1501.03154, Bibcode:2015ApJ...804..146D, doi:10.1088/0004-637X/804/2/146, S2CID 33401607.
  7. ^ "BP Boo". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-08-14.
  8. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  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. ^ Barentine, John C. (2016). The Lost Constellations: A History of Obsolete, Extinct, or Forgotten Star Lore. Springer. p. 304. ISBN 978-3-319-22794-8.
  11. ^ Wehlau, William (August 1962). "Photometry of γ Equulei and HD 140728". Publications of the Astronomical Society of the Pacific. 74 (439): 286–290. Bibcode:1962PASP...74..286W. doi:10.1086/127810. Retrieved 2 December 2024.
  12. ^ Watson, Christopher (January 4, 2010), "BP Boötis", AAVSO Website, American Association of Variable Star Observers, retrieved 3 August 2014.
  13. ^ Hatzes, Artie P. (July 1990), "The distribution of silicon on BP Boo", Monthly Notices of the Royal Astronomical Society, 245: 56, Bibcode:1990MNRAS.245...56H, doi:10.1093/mnras/245.1.56.