Upsilon Ophiuchi

Upsilon Ophiuchi
Location of υ Ophiuchi (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ophiuchus
Right ascension 16h 27m 48.18720s[1]
Declination −8° 22′ 18.2245″[1]
Apparent magnitude (V) 4.62[2]
Characteristics
Spectral type kA2hA5VmA5[3]
U−B color index +0.06[4]
B−V color index +0.16[4]
Astrometry
Radial velocity (Rv)−30.60[5] km/s
Proper motion (μ) RA: −67.49[1] mas/yr
Dec.: −11.75[1] mas/yr
Parallax (π)24.42 ± 0.91 mas[1]
Distance134 ± 5 ly
(41 ± 2 pc)
Absolute magnitude (MV)1.75[2]
Orbit[6]
PrimaryAa
CompanionAb
Period (P)27.218±0.0005 d
Semi-major axis (a)≥ 0.0583 AU
Eccentricity (e)0.744±0.002
Periastron epoch (T)2,438,914.84±0.01 JD
Argument of periastron (ω)
(secondary)		333.7±0.7°
Semi-amplitude (K1)
(primary)		34.9±0.3 km/s
Semi-amplitude (K2)
(secondary)		41.1±0.3 km/s
Orbit[7]
PrimaryA
CompanionB
Period (P)82.8±1.4 yr
Semi-major axis (a)0.79±0.03″
Eccentricity (e)0.45±0.03
Inclination (i)31.2±5.7°
Longitude of the node (Ω)86.8±6.9°
Periastron epoch (T)B 1994.1±1.0
Argument of periastron (ω)
(secondary)		177.9±7.4°
Details
Mass1.94[8] M☉
Radius1.9[8] R☉
Luminosity16.56[2] L☉
Surface gravity (log g)4.45[9] cgs
Temperature8,364[9] K
Metallicity [Fe/H]+0.14[2] dex
Rotational velocity (v sin i)44[10] km/s
Other designations
Alkarab, υ Oph, 3 Ophiuchi, BD−08°4243, FK5 3299, GC 22134, HD 148367, HIP 80628, HR 6129, SAO 141187, CCDM J16278-0822AB, WDS J16278-0822[11]
Database references
SIMBADdata

Upsilon Ophiuchi is a triple star[12] system in the equatorial constellation of Ophiuchus. It has a white hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.62.[2] The distance to this system is approximately 134 light years based on parallax.[1] It is drifting closer with a radial velocity of −30.6 km/s.[5]

The variable radial velocity of the brighter component was first observed by H. A. Abt in 1961. It is a double-lined spectroscopic binary system with an orbital period of 27.2 days and an eccentricity of 0.74.[6] They have a combined magnitude of 4.71. Both components are similar stars with a combined stellar classification of kA2hA5VmA5, and one or both are Am stars.[3] The third component has an 82.8 year orbit with the inner pair at an eccentricity of 0.45.[7] The system is a source for X-ray emission.[13]

References

  1. ^ a b c d e f Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600. Vizier catalog entry
  2. ^ a b c d e 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. S2CID 119257644. Vizier catalog entry
  3. ^ a b Abt, Helmut A.; Morrell, Nidia I. (1995). "The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars". Astrophysical Journal Supplement. 99: 135. Bibcode:1995ApJS...99..135A. doi:10.1086/192182.
  4. ^ a b Mallama, A. (2014). "Sloan Magnitudes for the Brightest Stars". The Journal of the American Association of Variable Star Observers. 42 (2): 443. Bibcode:2014JAVSO..42..443M.Vizier catalog entry
  5. ^ a b Wilson, R. E. (1953). "General Catalogue of Stellar Radial Velocities". Carnegie Institute Washington D.C. Publication. Carnegie Institution for Science. Bibcode:1953GCRV..C......0W. ISBN 9780598216885. LCCN 54001336.
  6. ^ a b Gutmann, F. (1965). "A study of the spectroscopic binary 3nu Ophiuchi (HD 148367)". Publications of the Dominion Astrophysical Observatory Victoria. 12: 391–399. Bibcode:1965PDAO...12..391G.
  7. ^ a b "Sixth Catalog of Orbits of Visual Binary Stars". United States Naval Observatory. Archived from the original on 1 August 2017. Retrieved 24 May 2017.
  8. ^ a b 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. arXiv:astro-ph/9911002. Bibcode:1999A&A...352..555A. Vizier catalog entry
  9. ^ a b 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. arXiv:1501.03154. Bibcode:2015ApJ...804..146D. doi:10.1088/0004-637X/804/2/146. S2CID 33401607. Vizier catalog entry
  10. ^ 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.
  11. ^ "ups Oph". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-10-21.{{cite web}}: CS1 maint: postscript (link)
  12. ^ Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976. Vizier catalog entry
  13. ^ Schröder, C.; Schmitt, J. H. M. M. (November 2007), "X-ray emission from A-type stars", Astronomy and Astrophysics, 475 (2): 677–684, Bibcode:2007A&A...475..677S, doi:10.1051/0004-6361:20077429