Iota Ophiuchi

ι Ophiuchi, Latinized as Iota Ophiuchi, is a single[11] star in the equatorial constellation of Ophiuchus, positioned near the constellation border with Hercules. It makes a naked-eye double with nearby Kappa Ophiuchi,[12] appearing as a faint, blue-white hued star with an apparent visual magnitude of 4.39.[2] The star is approximately 245 light years from the Sun based on parallax,[1] but is drifting closer with a radial velocity of −19 km/s.[6]

Iota Ophiuchi
Location of ι Ophiuchi (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ophiuchus
Right ascension  16h 54m 00.47151s[1]
Declination 10° 09′ 55.2982″[1]
Apparent magnitude (V) 4.39[2]
Characteristics
Evolutionary stage main sequence[3]
Spectral type B8V[4]
U−B color index −0.32[5]
B−V color index −0.08[5]
Astrometry
Radial velocity (Rv)−19.0±1.6[6] km/s
Proper motion (μ) RA: −53.80[1] mas/yr
Dec.: −34.04[1] mas/yr
Parallax (π)13.30 ± 0.22[1] mas
Distance245 ± 4 ly
(75 ± 1 pc)
Absolute magnitude (MV)0.01[2]
Details
Mass3.14±0.03[3] M☉
Radius2.8[7] R☉
Luminosity141+6
−5[3] L☉
Surface gravity (log g)4.03[8] cgs
Temperature11,220±78[3] K
Metallicity [Fe/H]+0.09[8] dex
Rotational velocity (v sin i)124[3] km/s
Age217[9] Myr
Other designations
ι Oph, 25 Oph, BD+10°3092, FK5 1442, GC 22775, HD 152614, HIP 82673, HR 6281, SAO 102458[10]
Database references
SIMBADdata

This object is a B-type main-sequence star with a stellar classification of B8V.[4] It is an estimated 217[9] million years old with a moderately high rate of spin, showing a projected rotational velocity of 124 km/s.[3] The star has 3.1[3] times the mass of the Sun and around 2.8[7] times the Sun's radius. Iota Ophiuchi is radiating 141[3] times the luminosity of the Sun from its photosphere at an effective temperature of 11,220 K.[3] It displays an infrared excess, suggesting the presence of circumstellar material.[13]

References
  1. 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
  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. Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars". Astronomy & Astrophysics. 537: A120. arXiv:1201.2052. Bibcode:2012A&A...537A.120Z. doi:10.1051/0004-6361/201117691. Vizier catalog entry
  4. Cowley, A. (November 1972). "Spectral classification of the bright B8 stars". Astronomical Journal. 77: 750–755. Bibcode:1972AJ.....77..750C. doi:10.1086/111348.
  5. 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
  6. 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.
  7. 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. arXiv:astro-ph/9911002. Bibcode:1999A&A...352..555A. Vizier catalog entry
  8. Wu, Yue; et al. (2010). "Coudé-feed stellar spectral library – atmospheric parameters". Astronomy & Astrophysics. 525: A71. arXiv:1009.1491. Bibcode:2011A&A...525A..71W. doi:10.1051/0004-6361/201015014.
  9. Gontcharov, G. A. (November 2012). "Spatial distribution and kinematics of OB stars". Astronomy Letters. 38 (11): 694–706. arXiv:1606.09028. Bibcode:2012AstL...38..694G. doi:10.1134/S1063773712110035.
  10. "iot Oph". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-05.
  11. 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.
  12. Arnold, H. J. P.; et al. (1999). The Photographic Atlas of the Stars. CRC Press. p. 156. ISBN 9780750306546.
  13. McDonald, I.; et al. (2012). "Fundamental parameters and infrared excesses of Hipparcos stars". Monthly Notices of the Royal Astronomical Society. 427: 343. arXiv:1208.2037. Bibcode:2012MNRAS.427..343M. doi:10.1111/j.1365-2966.2012.21873.x.
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