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68 Ophiuchi

Topic: Astronomy

 From HandWiki - Reading time: 3 min
Short description: Binary star system in the constellation Ophiuchus
68 Ophiuchi
Ophiuchus constellation map.svg
Red circle.svg
Location of 68 Ophiuchi (circled)
Observation data
Equinox J2000.0]] (ICRS)
Constellation Ophiuchus
Right ascension  18h 01m 45.19884s[1]
Declination 1° 18′ 18.2775″[1]
Apparent magnitude (V) 4.42[2] + 7.48[3]
Characteristics
Spectral type A2Vn[4]
U−B color index +0.02[5]
B−V color index +0.04[5]
Astrometry
Radial velocity (Rv)+6.00[6] km/s
Proper motion (μ) RA: +15.93[1] mas/yr
Dec.: -13.29[1] mas/yr
Parallax (π)11.15 ± 0.60[1] mas
Distance290 ± 20 ly
(90 ± 5 pc)
Absolute magnitude (MV)-0.34[2]
Orbit[7]
Period (P)175.74±4.65 yr
Semi-major axis (a)1.090±0.027″
Eccentricity (e)0.831±0.035
Inclination (i)69.5±3.0°
Longitude of the node (Ω)160.2±1.6°
Periastron epoch (T)2019.87±1.48
Argument of periastron (ω)
(secondary)		78.9±4.7°
Details
68 Oph A
Mass3.07[8] M☉
Radius4.5[9] R☉
Luminosity160[8] L☉
Surface gravity (log g)3.76[10] cgs
Temperature9,594[8] K
Metallicity [Fe/H]-0.14[11] dex
Rotational velocity (v sin i)201[8] km/s
Other designations
BD+01°3560, CCDM J18018+0118AB, GC 24534, HIP 88290, HR 6723, HD 164577, NSV 10009, SAO 123035, WDS J18018+0118AB
Database references
SIMBADdata

68 Ophiuchi is a binary star system in the equatorial constellation of Ophiuchus. It is visible to the naked eye as a faint star with an apparent visual magnitude of 4.42.[2] The system is located around 89.69 parsecs (292.5 ly) distant from the Sun, based on parallax,[1] and is drifting further away with a radial velocity of +6 km/s.[6]

This is a spectroscopic binary with an orbital period of 177 years and an eccentricity of 0.83.[7] The brighter member, component A, is an A-type main-sequence star of spectral type A2Vn,[4] a star that is currently fusing its core hydrogen. The 'n' suffix indicates "nebulous" lines due to rapid rotation. The star is suspected of varying between magnitudes 4.42 and 4.48.[12] It displays an infrared excess that matches a circumstellar disk of dust orbiting 32.5 astronomical unit|AU from the star with a mean temperature of 160 K.[13] The secondary companion, component B, is of magnitude 7.48.[3][14]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics 474 (2): 653–664. doi:10.1051/0004-6361:20078357. Bibcode: 2007A&A...474..653V.  Vizier catalog entry
  2. ↑ 2.0 2.1 2.2 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A.  Vizier catalog entry
  3. ↑ 3.0 3.1 Malkov, O. Yu.; Tamazian, V. S.; Docobo, J. A.; Chulkov, D. A. (2012). "Dynamical masses of a selected sample of orbital binaries". Astronomy & Astrophysics 546: A69. doi:10.1051/0004-6361/201219774. Bibcode: 2012A&A...546A..69M.  Vizier catalog entry
  4. ↑ 4.0 4.1 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. 
  5. ↑ 5.0 5.1 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
  6. ↑ 6.0 6.1 Gontcharov, G. A. (2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters 32 (11): 759–771. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G. 
  7. ↑ 7.0 7.1 Hartkopf, William I.; Mason, Brian D. (2009). "Speckle Interferometry at Mount Wilson Observatory: Observations Obtained in 2006-2007 and 35 New Orbits". The Astronomical Journal 138 (3): 813–826. doi:10.1088/0004-6256/138/3/813. Bibcode: 2009AJ....138..813H. 
  8. ↑ 8.0 8.1 8.2 8.3 Zorec, J.; Royer, F. (2012). "Rotational velocities of A-type stars". Astronomy & Astrophysics 537: A120. doi:10.1051/0004-6361/201117691. Bibcode: 2012A&A...537A.120Z.  Vizier catalog entry
  9. ↑ 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. Bibcode: 1999A&A...352..555A.  Vizier catalog entry
  10. ↑ 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. Bibcode: 2015ApJ...804..146D.  Vizier catalog entry
  11. ↑ Wu, Yue; Singh, H. P.; Prugniel, P.; Gupta, R.; Koleva, M. (2010). "Coudé-feed stellar spectral library – atmospheric parameters". Astronomy & Astrophysics 525: A71. doi:10.1051/0004-6361/201015014. Bibcode: 2011A&A...525A..71W. 
  12. ↑ VSX (17 December 2005). "NSV 10009". AAVSO Website. American Association of Variable Star Observers. http://www.aavso.org/vsx/index.php?view=detail.top&oid=48633. 
  13. ↑ Cotten, Tara H.; Song, Inseok (July 2016), "A Comprehensive Census of Nearby Infrared Excess Stars", The Astrophysical Journal Supplement Series 225 (1): 24, doi:10.3847/0067-0049/225/1/15, 15, Bibcode: 2016ApJS..225...15C. 
  14. ↑ Cvetkovic, Z.; Ninkovic, S. (2010). "On the Component Masses of Visual Binaries". Serbian Astronomical Journal 180 (180): 71. doi:10.2298/SAJ1080071C. Bibcode: 2010SerAJ.180...71C. 



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