Chi Ophiuchi

χ Ophiuchi
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Ophiuchus
Right ascension 16h 27m 01.4349s[1]
Declination −18° 27 22.504[1]
Apparent magnitude (V) 4.18 to 5.0[2]
Characteristics
Spectral type B2Vne[1]
U−B color index −0.75[3]
B−V color index +0.28[3]
R−I color index +0.22[3]
Variable type GCAS[2] + LERI[4]
Astrometry
Radial velocity (Rv)−3.2 ± 5[1] km/s
Proper motion (μ) RA: −5.58[1] mas/yr
Dec.: −22.22[1] mas/yr
Parallax (π)6.67 ± 0.74[1] mas
Distanceapprox. 490 ly
(approx. 150 pc)
Absolute magnitude (MV)−4.6[5]
Details
Mass10.1 ± 0.7[6] M
Radius4.5[7] R
Luminosity200,000[5] L
Surface gravity (log g)4.13[5] cgs
Temperature41,700[5] K
Rotational velocity (v sin i)134[3] km/s
Age22.5 ± 2.6[6] Myr
Other designations
χ Oph, Chi Ophiuchi, Chi Oph, 7 Ophiuchi, 7 Oph, BD−18 4282, FK5 3298, GC 22117, HD 148184, HIP 80569, HR 6118, PPM 231703, SAO 159918.[1]
Database references
SIMBADdata

Chi Ophiuchi (Chi Oph / χ Ophiuchi / χ Oph) is a Be star in the constellation of Ophiuchus.[1] It has an apparent visual magnitude which varies between 4.18 and 5.0.[2]

This star is a 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.[5]

References

  1. 1 2 3 4 5 6 7 8 9 * chi Oph -- Be Star, database entry, SIMBAD. Accessed on line January 12, 2011.
  2. 1 2 3 khi Oph, database entry, The combined table of GCVS Vols I-III and NL 67-78 with improved coordinates, General Catalogue of Variable Stars, Sternberg Astronomical Institute, Moscow, Russia. Accessed on line January 12, 2011.
  3. 1 2 3 4 HR 6118, database entry, The Bright Star Catalogue, 5th Revised Ed. (Preliminary Version), D. Hoffleit and W. H. Warren, Jr., CDS ID V/50. Accessed on line January 12, 2011.
  4. Watson, C. L. (2006). "The International Variable Star Index (VSX)". The Society for Astronomical Sciences 25th Annual Symposium on Telescope Science. Held May 23-25 25: 47. Bibcode:2006SASS...25...47W.
  5. 1 2 3 4 5 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
  6. 1 2 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
  7. HD 148184, database entry, Catalog of Apparent Diameters and Absolute Radii of Stars (CADARS), 3rd edition, L. E. Pasinetti-Fracassini, L. Pastori, S. Covino, and A. Pozzi, CDS ID II/224. Accessed on line January 12, 2011.
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