Astronomy:HD 201507

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Short description: High proper motion star in the constellation Equuleus
HD 201507
Location of HD 201507 (circled)
Observation data
Epoch J2000.0   Equinox (celestial coordinates)
Constellation Equuleus[1]
Right ascension  21h 09m 58.2645s[2]
Declination +02° 56′ 37.310″[2]
Apparent magnitude (V) 6.43±0.01[3]
Characteristics
Evolutionary stage subgiant[4]
Spectral type F5 IV[5]
U−B color index +0.06[6]
B−V color index +0.37[6]
Astrometry
Radial velocity (Rv)−42.8±2.4[7] km/s
Proper motion (μ) RA: +48.902[2] mas/yr
Dec.: +10.883[2] mas/yr
Parallax (π)15.2530 ± 0.3122[2] mas
Distance214 ± 4 ly
(66 ± 1 pc)
Absolute magnitude (MV)+2.12[1]
Details
Mass1.45±0.23[8] M☉
Radius2.2±0.1[8] R☉
Luminosity9.147±0.21[2] L☉
Surface gravity (log g)3.91±0.09[8] cgs
Temperature6,846±233[9] K
Metallicity [Fe/H]+0.09[10] dex
Rotational velocity (v sin i)16.4±10.6[11] km/s
Age1.21[9] Gyr
Other designations
BD+02°4311, GC 29582, HD 201507, HIP 104481, HR 8095, SAO 126587[12]
Database references
SIMBADdata

HD 201507, also designated HR 8095, is a white-hued star located in the equatorial constellation Equuleus. It has an apparent magnitude of 6.43,[3] placing it near the limit for naked eye visibility. Parallax measurements place the object at a distance of 214 light years[2] and it is currently drifting closer with a heliocentric radial velocity of −43 km/s.[7]

There have been disagreements in classifying the star's spectrum. Eugene A. Harlan found a spectral classification of F5 IV,[5] indicating that it is a F-type subgiant that is evolving towards the red giant branch. On the other hand, Nancy Houk and Carrie Swift (1999) found a class of F2 V,[13] indicating that it is still on the main sequence.

HD 201507 has 1.45 times the mass of the Sun and a slightly enlarged radius of 2.2 R☉[8] due to its evolved state. It shines with a luminosity of about 9 L☉[2] from its photosphere at an effective temperature of 6,846 K.[9] HD 201507 is slightly metal enriched, with a metallicity 123% that of the Sun.[10] This star has a modest projected rotational velocity of 16 km/s[11] and is estimated to be 1.21 billion years old,[9] only a quarter the age of the Sun.

References

  1. ↑ 1.0 1.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A  XHIP record for this object at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 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. Bibcode: 2018A&A...616A...1G.  Gaia DR2 record for this source at VizieR.
  3. ↑ 3.0 3.1 Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P. et al. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics 355: L27–L30. ISSN 0004-6361. Bibcode: 2000A&A...355L..27H. 
  4. ↑ ((do Nascimento, J. D., Jr.)); Canto Martins, B. L.; Melo, C. H. F.; Porto De Mello, G.; De Medeiros, J. R. (2003). "On the link between rotation, chromospheric activity and Li abundance in subgiant stars". Astronomy and Astrophysics 405 (2): 723. doi:10.1051/0004-6361:20030633. Bibcode: 2003A&A...405..723D. 
  5. ↑ 5.0 5.1 Harlan, E. A. (June 1974). "MK classifications for F-and G-type stars. 3.". The Astronomical Journal 79: 682. doi:10.1086/111597. ISSN 0004-6256. Bibcode: 1974AJ.....79..682H. 
  6. ↑ 6.0 6.1 Cousins, A. W. J. (1971). "Photometric standard stars". Royal Observatory Annals 7. Bibcode: 1971ROAn....7.....C. 
  7. ↑ 7.0 7.1 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. doi:10.1134/S1063773706110065. ISSN 1063-7737. Bibcode: 2006AstL...32..759G. 
  8. ↑ 8.0 8.1 8.2 8.3 Stassun, Keivan G. et al. (9 September 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. ISSN 0004-6256. Bibcode: 2019AJ....158..138S. 
  9. ↑ 9.0 9.1 9.2 9.3 David, Trevor J.; Hillenbrand, Lynne A. (12 May 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. Bibcode: 2015ApJ...804..146D. 
  10. ↑ 10.0 10.1 Netopil, Martin (4 May 2017). "Metallicity calibrations for dwarf stars and giants in the Geneva photometric system". Monthly Notices of the Royal Astronomical Society 469 (3): 3042–3055. doi:10.1093/mnras/stx1077. ISSN 0035-8711. Bibcode: 2017MNRAS.469.3042N. 
  11. ↑ 11.0 11.1 De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (January 2014). "A catalog of rotational and radial velocities for evolved stars: V. Southern stars⋆⋆⋆". Astronomy & Astrophysics 561: A126. doi:10.1051/0004-6361/201220762. ISSN 0004-6361. Bibcode: 2014A&A...561A.126D. 
  12. ↑ "HD 201507". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+201507. 
  13. ↑ Houk, Nancy; Swift, Carrie (1999). Michigan catalogue of two-dimensional spectral types for the HD Stars; vol. 5. Bibcode: 1999mctd.book.....H. 
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