Star in the constellation Ophiuchus
Theta Ophiuchi
Location of θ Ophiuchi (circled)
Observation dataEpoch J2000 Equinox J2000
Constellation
Ophiuchus
Right ascension 17h 22m 00.57935s [ 1]
Declination
−24° 59′ 58.3670″[ 1]
Apparent magnitude (V)3.25 - 3.31[ 2]
Characteristics
Spectral type
B2 IV[ 3]
U−B color index
−0.86[ 4]
B−V color index
−0.23[ 4]
Variable type
β Cep [ 2]
Astrometry Radial velocity (Rv )−2[ 5] km/s Proper motion (μ) RA: −7.37[ 1] mas /yr Dec.: −23.94[ 1] mas /yr Parallax (π)7.48± 0.17 mas [ 1] Distance 436 ± 10 ly pc ) Absolute magnitude (MV )−2.4[ 6] Details θ Oph Aa Mass [ 7] M ☉ Radius [ 7] R ☉ Luminosity [ 7] L ☉ Surface gravity (log g )± 0.006[ 8] cgs Temperature ± 280[ 8] K Metallicity [Fe/H] ± 0.12[ 9] dex Rotational velocity (v sin i )30[ 10] Age [ 7] Myr θ Oph B Mass 5.4[ 7] M ☉ Radius [ 7] R ☉ Luminosity [ 7] L ☉ Surface gravity (log g )[ 7] cgs Temperature 17,700[ 7] K Rotational velocity (v sin i )150[ 7] Age [ 7] Myr Other designations θ Ophiuchi , 42 Ophiuchi , CD −24 13292FK5 644GC 23451HD 157056HIP 84970HR 6453SAO 185320[ 11] Database references SIMBAD data
Theta Ophiuchi , Latinized from θ Ophiuchi, is a multiple star system in the equatorial constellation of Ophiuchus . It lies on the "right foot" of the serpent-bearer, just southwest of Kepler's Star , the nova of 1604. This star has an apparent visual magnitude of +3.3,[ 6] readily visible to the naked eye. Based upon parallax measurements from the Hipparcos mission, it is roughly 436 light-years (134 parsecs ) from Earth.[ 1] lunar occultations and (very rarely) occulted by a planet. The next occultation by a planet will be by Mars on 3 October 2078.[ 12]
Theta Ophiuchi appears to be a triple star system. The brightest component is a spectroscopic binary with an orbital period of 56.71 days and an eccentricity of 0.17. The third component is 5.5 magnitude star with a stellar classification of B5 . Its angular separation from the binary pair is 0.15 arcseconds .[ 13] proper motion member of the Upper Scorpius sub-group in the Scorpius–Centaurus OB association , the nearest such co-moving association of massive stars to the Sun.[ 6]
A light curve for Theta Ophiuchi, plotted from Hipparcos [ 14] The primary component of this system is a variable star of the Beta Cephei type with a period of just 3h 22m.[ 15] mass of the Sun and 4.98 to 5.23 times the Sun's radius. Although only 15.8 to 24 million years old,[ 7] evolve away from the main sequence and has become a subgiant star with a stellar classification of B2 IV.[ 3] luminosity of the Sun from its photosphere [ 7] effective temperature of about 22,260 K,[ 8] B-type star .[ 16]
According to Richard H. Allen's Star Names : Their Lore and Meaningξ 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".[ 17] ζ Oph , η Oph, and ξ Oph it formed the Persian Garafsa , the Serpent-tamer;[ 17] [ 18]
References
^ a b c d e f van Leeuwen, Floor (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics , 474 (2): 653– 664, arXiv :0708.1752v1 Bibcode :2007A&A...474..653V , doi :10.1051/0004-6361:20078357 , S2CID 18759600 Note: see VizieR catalogue I/311 .^ a b 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 . S2CID 125853869 . ^ a b Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society 410 (1): 190– 200, arXiv :1007.4883 Bibcode :2011MNRAS.410..190T , doi :10.1111/j.1365-2966.2010.17434.x S2CID 118629873 ^ a b Johnson, H. L.; et al. (1966), "UBVRIJKL photometry of the bright stars", Communications of the Lunar and Planetary Laboratory , 4 (99): 99, Bibcode :1966CoLPL...4...99J ^ Evans, D. S. (June 20–24, 1966), Batten, Alan Henry; Heard, John Frederick (eds.), "The Revision of the General Catalogue of Radial Velocities", Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30 , vol. 30, University of Toronto: International Astronomical Union , p. 57, Bibcode :1967IAUS...30...57E ^ a b c de Geus, E. J.; de Zeeuw, P. T.; Lub, J. (June 1989), "Physical parameters of stars in the Scorpio-Centaurus OB association", Astronomy and Astrophysics , 216 (1– 2): 44– 61, Bibcode :1989A&A...216...44D ^ a b c d e f g h i j k l m Walczak, Przemysław; Daszyńska-Daszkiewicz, Jadwiga; Pigulski, Andrzej; Pamyatnykh, Alexey; Moffat, Anthony F J; Handler, Gerald; Pablo, Herbert; Popowicz, Adam; Wade, Gregg; Weiss, Werner W; Zwintz, Konstanze (2019-05-21). "Seismic modelling of early B-type pulsators observed by BRITE – I. θ Ophiuchi" . Monthly Notices of the Royal Astronomical Society . 485 (3): 3544– 3557. arXiv :1903.04224 Bibcode :2019MNRAS.485.3544W . doi :10.1093/mnras/stz639 ISSN 0035-8711 . ^ a b c Briquet, M.; Morel, T.; Thoul, A.; Scuflaire, R.; Miglio, A.; Montalbán, J.; Dupret, M.-A.; Aerts, C. (November 2007), "An asteroseismic study of the β Cephei star θ Ophiuchi: constraints on global stellar parameters and core overshooting" (PDF) , Monthly Notices of the Royal Astronomical Society , 381 (4): 1482– 1488, arXiv :0706.3274 Bibcode :2007MNRAS.381.1482B , doi :10.1111/j.1365-2966.2007.12142.x S2CID 18255593 ^ Daszyńska-Daszkiewicz, J.; Niemczura, E. (April 2005), "Metallicity of mono- and multiperiodic β Cephei stars", Astronomy and Astrophysics , 433 (3): 1031– 1035, arXiv :astro-ph/0410442 Bibcode :2005A&A...433.1031D , doi :10.1051/0004-6361:20040397 , S2CID 119340011 ^ Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal , 573 (1): 359– 365, Bibcode :2002ApJ...573..359A , doi :10.1086/340590 ^ "tet Oph" , SIMBAD Centre de données astronomiques de Strasbourg , retrieved 2007-01-21 ^ Stellarium Labs (n.d.). "Stellarium Web Online Star Map" . Stellarium Web . Retrieved 2025-02-23 . ^ 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 S2CID 14878976 ^ "Light Curve" , Hipparcos ESA , ESA, retrieved 20 August 2022 ^ Burnham, Robert (1978), Burnham's celestial handbook: an observer's guide to the universe beyond the solar system 1372 , ISBN 978-0-486-23673-5 ^ "The Colour of Stars" , Australia Telescope, Outreach and Education , Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2013-12-03, retrieved 2012-01-16 ^ a b Allen, R.H. (1899), Star Names: Their Lore and Meaning ^ Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars (PDF) , Jet Propulsion Laboratory, California Institute of Technology.
