Astronomy:Xi Ophiuchi

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Short description: Visual binary star system in the constellation Ophiuchus
Xi Ophiuchi
Ophiuchus constellation map.svg
Red circle.svg
Location of ξ Ophiuchi (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Ophiuchus
Right ascension  17h 21m 00.37452s[1]
Declination −21° 06′ 46.5710″[1]
Apparent magnitude (V) 4.39[2]
Characteristics
Spectral type F2V[3]
U−B color index -0.06[4]
B−V color index +0.41[4]
Astrometry
Radial velocity (Rv)−8.73±0.12[1] km/s
Proper motion (μ) RA: +265.543[1] mas/yr
Dec.: -202.584[1] mas/yr
Parallax (π)57.0820 ± 0.1851[1] mas
Distance57.1 ± 0.2 ly
(17.52 ± 0.06 pc)
Absolute magnitude (MV)3.19[2]
Details[5]
A
Mass1.30 M
Radius1.59±0.06 R
Luminosity4.429±0.035[6] L
Surface gravity (log g)4.15±0.10 cgs
Temperature6,611±80 K
Metallicity [Fe/H]−0.27±0.07 dex
Rotational velocity (v sin i)20.2±0.7 km/s
Age916[7] Myr
Other designations
ξ Oph, 40 Ophiuchi, BD−20°4731, FK5 917, GC 23423, HD 156897, HIP 84893, HR 6445, SAO 185296, CCDM J17210-2107AB, WDS J17210-2107AB, LTT 6908[8]
Database references
SIMBADdata

ξ Oph, Latinized as Xi Ophiuchi, is a visual binary star[9] system in the equatorial constellation of Ophiuchus.[2] It has a yellow-white hue and is faintly visible to the naked eye with a combined apparent visual magnitude of 4.39.[2] The system is located approximately 57.1 light-years (17.5 parsecs) away from the Sun based on parallax, but is drifting closer with a radial velocity of -9 km/s.[1]

The magnitude 4.40[10] primary, designated component A, is an ordinary F-type main-sequence star with a stellar classification of F2V.[3] It is 916[7] million years old and is rotating with a projected rotational velocity of 20 km/s. The star has 1.3 times the mass of the Sun and 1.6 times the Sun's radius.[5] It is radiating 4.4[6] times the luminosity of the Sun from its photosphere at an effective temperature of 6,611 K.[5]

The system is a source of X-ray emission.[11] The orbiting companion, component B, is a magnitude 8.9 star at an angular separation of 35 along a position angle of 27° from the primary, as of 2015. A magnitude 10.8 visual companion, component C, lies at a separation of 10.8″, as of 2004.[10]

According to Richard H. Allen's Star Names: Their Lore and Meaning (1899), ξ Oph together with θ Oph formed the Sogdian Wajrik "the Magician", the Khorasmian Markhashik "the Serpent-bitten" and with η Oph the Coptic Tshiō, "the Snake", and Aggia, "the Magician".[12]

References

  1. 1.0 1.1 1.2 1.3 1.4 1.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  2. 2.0 2.1 2.2 2.3 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode2012AstL...38..331A.  Vizier catalog entry
  3. 3.0 3.1 Gray, R. O.; Corbally, C. J.; Garrison, R. F.; McFadden, M. T.; Bubar, E. J.; McGahee, C. E.; O'Donoghue, A. A.; Knox, E. R. (2006). "Contributions to the Nearby Stars (NStars) Project: Spectroscopy of Stars Earlier than M0 within 40 pc--The Southern Sample". The Astronomical Journal 132 (1): 161–170. doi:10.1086/504637. Bibcode2006AJ....132..161G. 
  4. 4.0 4.1 Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers 42 (2): 443. Bibcode2014JAVSO..42..443M. Vizier catalog entry
  5. 5.0 5.1 5.2 Fuhrmann, K.; Chini, R.; Kaderhandt, L.; Chen, Z. (2017). "Multiplicity among Solar-type Stars". The Astrophysical Journal 836 (1): 139. doi:10.3847/1538-4357/836/1/139. Bibcode2017ApJ...836..139F. 
  6. 6.0 6.1 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.  Gaia DR2 record for this source at VizieR.
  7. 7.0 7.1 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.  Vizier catalog entry
  8. "ksi Oph". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=ksi+Oph. 
  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. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode2008MNRAS.389..869E. 
  10. 10.0 10.1 Mason, Brian D. et al. (200). "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. Bibcode2001AJ....122.3466M.  Vizier catalog entry
  11. Haakonsen, Christian Bernt; Rutledge, Robert E. (September 2009). "XID II: Statistical Cross-Association of ROSAT Bright Source Catalog X-ray Sources with 2MASS Point Source Catalog Near-Infrared Sources". The Astrophysical Journal Supplement 184 (1): 138–151. doi:10.1088/0067-0049/184/1/138. Bibcode2009ApJS..184..138H. 
  12. Allen, R.H. (1899), Star Names: Their Lore and Meaning, p. 297, https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Ophiuchus*.html