Astronomy:72 Ophiuchi

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Short description: Binary star system in the constellation Ophiuchus
72 Ophiuchi
Ophiuchus constellation map.svg
Red circle.svg
Location of 72 Ophiuchi (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Ophiuchus
Right ascension  18h 07m 20.98393s[1]
Declination 9° 33′ 49.8501″[1]
Apparent magnitude (V) 3.73[2] + 14.0[3]
Characteristics
Spectral type A5 V[4]
U−B color index +0.10[2]
B−V color index +0.12[2]
Astrometry
Radial velocity (Rv)-23.90[5] km/s
Proper motion (μ) RA: -62.17[1] mas/yr
Dec.: +79.66[1] mas/yr
Parallax (π)37.55 ± 0.21[1] mas
Distance86.9 ± 0.5 ly
(26.6 ± 0.1 pc)
Absolute magnitude (MV)1.58[6]
Details
Mass1.99[7] M☉
Radius1.9[8] R☉
Luminosity20[7] L☉
Surface gravity (log g)4.04[9] cgs
Temperature8,718[9] K
Metallicity [Fe/H]+0.09[6] dex
Rotational velocity (v sin i)65[7] km/s
Age250[9] Myr
Other designations
72 Oph, BD+09°3564, FK5 680, GC 24695, GJ 9615 A, HD 165777, HIP 88771, HR 6771, SAO 123142, CCDM J18073+0934A, WDS J18073+0934A[10]
Database references
SIMBADdata

72 Ophiuchi is a binary star[3] system in the equatorial constellation of Ophiuchus. It is visible to the naked eye as a faint, white-hued point of light with a combined apparent visual magnitude of 3.73.[2] It is located approximately 86.9 light years away from the Sun based on parallax,[1] but is moving closer with a heliocentric radial velocity of -23.9 km/s.[5]

As of 2008, the pair had an angular separation of 25″.[3] According to Gray et al. (2003), the primary component has a stellar classification of A5 V,[4] matching an A-type main-sequence star. Cowley et al. (1969) had assigned it to a class of A4 IVs,[11] suggesting it is a sharp-lined (s) subgiant star. The latter class is still in use by some sources.[7][3][12]

The primary is 250[9] million years old with double[7] the mass of the Sun and is spinning with a moderate projected rotational velocity of 65 km/s.[7] It is radiating 20[7] times the luminosity of the Sun from its photosphere at an effective temperature of 8,718 K.[9] It displays an infrared excess, suggesting a debris disk is orbiting the star with a mean separation of 82.96 astronomical unit|AU and temperature of 60 K.[13] The system is a source of X-ray emission,[12] which is most likely coming from the 14th[3] magnitude companion.[12]

There are additional visual companions: component C with magnitude 11.5 lies at an angular separation of 64″ from the primary,[14] while component D, has magnitude 14.8 and separation 24".[15]

This star was once considered part of the obsolete constellation Taurus Poniatovii, the brightest star in it. After the International Astronomical Union officially recognised constellations, it was placed in Ophiuchus.[16]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V.  Vizier catalog entry
  2. ↑ 2.0 2.1 2.2 2.3 Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues 2237. Bibcode: 2002yCat.2237....0D. 
  3. ↑ 3.0 3.1 3.2 3.3 3.4 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. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode: 2008MNRAS.389..869E. 
  4. ↑ 4.0 4.1 Gray, R. O. et al. (2003). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 Parsecs: The Northern Sample. I". The Astronomical Journal 126 (4): 2048. doi:10.1086/378365. Bibcode: 2003AJ....126.2048G. 
  5. ↑ 5.0 5.1 Kharchenko, N. V.; Scholz, R.-D.; Piskunov, A. E.; Röser, S.; Schilbach, E. (2007). "Astrophysical supplements to the ASCC-2.5: Ia. Radial velocities of ~55000 stars and mean radial velocities of 516 Galactic open clusters and associations". Astronomische Nachrichten 328 (9): 889. doi:10.1002/asna.200710776. Bibcode: 2007AN....328..889K. 
  6. ↑ 6.0 6.1 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.  Vizier catalog entry
  7. ↑ 7.0 7.1 7.2 7.3 7.4 7.5 7.6 Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars". Astronomy & Astrophysics 537: A120. doi:10.1051/0004-6361/201117691. Bibcode: 2012A&A...537A.120Z.  Vizier catalog entry
  8. ↑ Allende Prieto, C.; Lambert, D. L. (1999). "Fundamental parameters of nearby stars from the comparison with evolutionary calculations: Masses, radii and effective temperatures". Astronomy and Astrophysics 352: 555–562. Bibcode: 1999A&A...352..555A.  Vizier catalog entry
  9. ↑ 9.0 9.1 9.2 9.3 9.4 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. Bibcode: 2015ApJ...804..146D.  Vizier catalog entry
  10. ↑ "72 Oph". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=72+Oph. 
  11. ↑ 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. Bibcode: 1969AJ.....74..375C. 
  12. ↑ 12.0 12.1 12.2 De Rosa, R. J. et al. (July 2011). "The Volume-limited A-Star (VAST) survey - I. Companions and the unexpected X-ray detection of B6-A7 stars". Monthly Notices of the Royal Astronomical Society 415 (1): 854–866. doi:10.1111/j.1365-2966.2011.18765.x. Bibcode: 2011MNRAS.415..854D. 
  13. ↑ Gáspár, András et al. (2016). "The Correlation between Metallicity and Debris Disk Mass". The Astrophysical Journal 826 (2): 171. doi:10.3847/0004-637X/826/2/171. Bibcode: 2016ApJ...826..171G. 
  14. ↑ Renson, P.; Manfroid, J. (2009). "Catalogue of Ap, HgMn and Am stars". Astronomy and Astrophysics 498 (3): 961. doi:10.1051/0004-6361/200810788. Bibcode: 2009A&A...498..961R. 
  15. ↑ Mason, Brian D. et al. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal 122 (6): 3466. doi:10.1086/323920. Bibcode: 2001AJ....122.3466M.  Vizier catalog entry
  16. ↑ Ian Ridpath. "Taurus Poniatovii". http://www.ianridpath.com/startales/poniatowski.html. 



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