Astronomy:HD 28527

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Short description: Star in the constellation Taurus
HD 28527
Observation data
Equinox J2000.0]] (ICRS)
Constellation Taurus
Right ascension  04h 30m 33.633s[1]
Declination +16° 11′ 38.46″[1]
Apparent magnitude (V) 4.78[2]
Characteristics
Spectral type A6 IV[3] or A7 V[4]
B−V color index +0.170±0.001[2]
Variable type suspected δ Sct[5]
Astrometry
Radial velocity (Rv)+38.1±0.8[2] km/s
Proper motion (μ) RA: +104.422[1] mas/yr
Dec.: −26.254[1] mas/yr
Parallax (π)22.0357 ± 0.2516[1] mas
Distance148 ± 2 ly
(45.4 ± 0.5 pc)
Absolute magnitude (MV)+1.58[6]
Details
Mass1.75[7] M
Radius2.209[8] R
Luminosity19.03[2] L
Surface gravity (log g)4.17±0.14[7] cgs
Temperature8,274±281[7] K
Metallicity [Fe/H]+0.30[9] dex
Rotation1.278 d[8]
Rotational velocity (v sin i)87.5[8] km/s
Age307[7] Myr
Other designations
NSV 1627, BD+15°637, GJ 170.1/9157, HD 28527, HIP 21029, HR 1427, SAO 93975[10]
Database references
SIMBADdata
Hyades cluster, with HD 28527 (marked with a green arrow) just NE of the θ Tauri pair

HD 28527 is a star in the constellation Taurus, and a member of the Hyades open cluster.[8] It is faintly visible to the naked eye with an apparent visual magnitude of 4.78.[2] The distance to this star, as determined from its parallax shift of 22 mas,[1] is 148 light years. It is moving away from the Earth with a heliocentric radial velocity of +38 km/s.[2]

Based upon a stellar classification of A6 IV by Cowley et al. (1969),[3] this is an A-type subgiant star that has consumed the hydrogen at its core and is evolving away from the main sequence. Older studies had it classed as an A-type main-sequence star with a class of A7 V.[4] At the age of 307[7] million years, it has a high rate of spin, revolving upon its axis once every 1.278 days.[8] It is a Delta Scuti variable[5] with 1.75[7] times the mass of the Sun and 2.2[8] times the Sun's radius. The star is radiating 19[2] times the Sun's luminosity from its photosphere at an effective temperature of 8,274 K.[7]

Due to its location near the ecliptic, this star is subject to lunar occultations. These events have provided occasional, but not definitive, evidence of a close secondary companion.[11][12] Eggleton and Tokovinin (2008) catalogue this as a possible triple star system, having the inner pair being similar stars with an angular separation of 0.02, and the outer component a magnitude 6.7 star of class F2 at a much wider separation of 250″.[13]

See also

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode2018A&A...616A...1G. 
  2. 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode2012AstL...38..331A. 
  3. 3.0 3.1 Cowley, A. et al. (April 1969), "A study of the bright A stars. I. A catalogue of spectral classifications", Astronomical Journal 74: 375–406, doi:10.1086/110819, Bibcode1969AJ.....74..375C. 
  4. 4.0 4.1 Ljunggren, B.; Oja, T. (1961), "The Uppsala spectral classification", Uppsala Astronomical Observatory Annual 4 (10): 10, Bibcode1961UppAn...4j...1L. 
  5. 5.0 5.1 Samus', N. N. et al. (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports 61 (1): 80–88, doi:10.1134/S1063772917010085, Bibcode2017ARep...61...80S. 
  6. Eggen, Olin J. (July 1998), "The Age Range of Hyades Stars", The Astronomical Journal 116 (1): 284–292, doi:10.1086/300413, Bibcode1998AJ....116..284E. 
  7. 7.0 7.1 7.2 7.3 7.4 7.5 7.6 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, doi:10.1088/0004-637X/804/2/146, Bibcode2015ApJ...804..146D. 
  8. 8.0 8.1 8.2 8.3 8.4 8.5 van Saders, Jennifer L.; Pinsonneault, Marc H. (October 2013), "Fast Star, Slow Star; Old Star, Young Star: Subgiant Rotation as a Population and Stellar Physics Diagnostic", The Astrophysical Journal 776 (2): 20, doi:10.1088/0004-637X/776/2/67, 67, Bibcode2013ApJ...776...67V. 
  9. Gebran, M. et al. (November 2010), "Chemical composition of A and F dwarfs members of the Hyades open cluster", Astronomy and Astrophysics 523: A71, doi:10.1051/0004-6361/200913273, Bibcode2010A&A...523A..71G. 
  10. "HD 161840". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+161840. 
  11. Peterson, D. M.; Baron, R. L.; Dunham, E.; Mink, D.; Weekes, T. C.; Elliot, J. L. (February 1981), "Lunar occultations of the Hyades: 1979-1980", Astronomical Journal 86: 280–289, doi:10.1086/112886, Bibcode1981AJ.....86..280P. 
  12. Richichi, A. et al. (October 1999), "New binary stars discovered by lunar occultations. IV", Astronomy and Astrophysics 350: 491–496, Bibcode1999A&A...350..491R. 
  13. Eggleton, P. P.; Tokovinin, A. A. (2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society 389 (2): 869, doi:10.1111/j.1365-2966.2008.13596.x, Bibcode2008MNRAS.389..869E.