30 Ophiuchi

30 Ophiuchi is a single[10] star in the equatorial constellation of Ophiuchus, and is positioned 1° east-southeast of Messier 10.[11] It is visible to the naked eye as a faint, orange-hued point of light with an apparent visual magnitude of 4.82.[2] The distance to this star is approximately 350 light years based on parallax.[6] It is drifting closer to the Earth with a heliocentric radial velocity of −6.7 km/s.[5]

30 Ophiuchi
Location of 30 Ophiuchi (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ophiuchus
Right ascension  17h 01m 03.60142s[1]
Declination −4° 13′ 21.5308″[1]
Apparent magnitude (V) 4.82[2]
Characteristics
Spectral type K4III[3]
U−B color index +1.80[4]
B−V color index +1.48[4]
Astrometry
Radial velocity (Rv)−6.70[5] km/s
Proper motion (μ) RA: −39.13[6] mas/yr
Dec.: −78.09[6] mas/yr
Parallax (π)9.3138 ± 0.1676[1] mas
Distance350 ± 6 ly
(107 ± 2 pc)
Absolute magnitude (MV)−0.65[2]
Details
Radius35.89+0.54
−2.12[1] R☉
Luminosity299.8±6.2[1] L☉
Surface gravity (log g)1.73[7] cgs
Temperature4,009.00+126.67
−29.67[1] K
Metallicity [Fe/H]−0.03[2] dex
Rotational velocity (v sin i)1.4[8] km/s
Other designations
30 Oph, NSV 8111, BD−04°4215, FK5 1445, GC 22937, HD 153687, HIP 83262, HR 6318, SAO 141483, CCDM J17011-0413A, WDS J17011-0413A[9]
Database references
SIMBADdata

This is an aging giant star with a stellar classification of K4III,[3] having exhausted the supply of hydrogen at its core and expanded to 36[1] times the Sun's radius. It is a suspected variable star.[12] The star is radiating 300[1] times the luminosity of the Sun from its swollen photosphere at an effective temperature of 4,009 K.[1] It is emitting a far infrared excess due to circumstellar dust,[13] which extends out to a diameter of 240 AU and has a mass of 62×1025 g.[14]

The primary has two reported visual companions: component B, at magnitude 9.71 and separation 99.8", and C, at magnitude 8.75 and separation 220.9".[15]

References
  1. 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. 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. Vizier catalog entry
  3. Hoffleit, D.; Warren, W. H. (1995). "VizieR Online Data Catalog: Bright Star Catalogue, 5th Revised Ed. (Hoffleit+, 1991)". VizieR On-line Data Catalog: V/50. Originally Published in: 1964BS....C......0H. 5050. Bibcode:1995yCat.5050....0H.
  4. Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers. 42: 443. Bibcode:2014JAVSO..42..443M.Vizier catalog entry
  5. Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065.
  6. Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. Vizier catalog entry
  7. Soubiran, Caroline; Le Campion, Jean-François; Brouillet, Nathalie; Chemin, Laurent (2016). "The PASTEL catalogue: 2016 version". Astronomy & Astrophysics. 591: A118. arXiv:1605.07384. Bibcode:2016A&A...591A.118S. doi:10.1051/0004-6361/201628497.
  8. De Medeiros, J. R.; Alves, S.; Udry, S.; Andersen, J.; Nordström, B.; Mayor, M. (2014). "A catalog of rotational and radial velocities for evolved stars". Astronomy & Astrophysics. 561: A126. arXiv:1312.3474. Bibcode:2014A&A...561A.126D. doi:10.1051/0004-6361/201220762. Vizier catalog entry
  9. "30 Oph". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-06-19.
  10. 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.
  11. O'Meara, Stephen James (1998). Deep-Sky Companions: The Messier Objects. Cambridge University Press. p. 63. ISBN 9780521553322.
  12. Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085.
  13. Zuckerman, B.; et al. (June 1995). "Luminosity Class III Stars with Excess Far-Infrared Emission". Astrophysical Journal Letters. 446: L79. Bibcode:1995ApJ...446L..79Z. doi:10.1086/187935.
  14. Jura, M. (April 1999). "Dust around First-Ascent Red Giants". The Astrophysical Journal. 515 (2): 706–711. Bibcode:1999ApJ...515..706J. doi:10.1086/307064.
  15. Mason, Brian D.; Wycoff, Gary L.; Hartkopf, William I.; Douglass, Geoffrey G.; Worley, Charles E. (2001). "The 2001 US Naval Observatory Double Star CD-ROM. I. The Washington Double Star Catalog". The Astronomical Journal. 122 (6): 3466. Bibcode:2001AJ....122.3466M. doi:10.1086/323920. Vizier catalog entry
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