72 Ophiuchi

72 Ophiuchi
Location of 72 Ophiuchi (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ophiuchus
Right ascension 18h 07m 20.98393s[1]
Declination 9° 33′ 49.8501″[1]
Apparent magnitude (V) 3.73[2] + 14.0[3]
Characteristics
Spectral type A5 V[4]
U−B color index +0.10[2]
B−V color index +0.12[2]
Astrometry
Radial velocity (Rv)-23.90[5] km/s
Proper motion (μ) RA: -62.17[1] mas/yr
Dec.: +79.66[1] mas/yr
Parallax (π)37.55 ± 0.21 mas[1]
Distance86.9 ± 0.5 ly
(26.6 ± 0.1 pc)
Absolute magnitude (MV)1.58[6]
Details
Mass1.99[7] M☉
Radius1.9[8] R☉
Luminosity20[7] L☉
Surface gravity (log g)4.04[9] cgs
Temperature8,718[9] K
Metallicity [Fe/H]+0.09[6] dex
Rotational velocity (v sin i)65[7] km/s
Age250[9] Myr
Other designations
72 Oph, BD+09°3564, FK5 680, GC 24695, GJ 9615 A, HD 165777, HIP 88771, HR 6771, SAO 123142, CCDM J18073+0934A, WDS J18073+0934A[10]
Database references
SIMBADdata

72 Ophiuchi is a binary star[3] system in the equatorial constellation of Ophiuchus. It is visible to the naked eye as a faint, white-hued point of light with a combined apparent visual magnitude of 3.73.[2] It is located approximately 86.9 light years away from the Sun based on parallax,[1] but is moving closer with a heliocentric radial velocity of -23.9 km/s.[5]

As of 2008, the pair had an angular separation of 25″.[3] According to Gray et al. (2003), the primary component has a stellar classification of A5 V,[4] matching an A-type main-sequence star. Cowley et al. (1969) had assigned it to a class of A4 IVs,[11] suggesting it is a sharp-lined (s) subgiant star. The latter class is still in use by some sources.[7][3][12]

The primary is 250[9] million years old with double[7] the mass of the Sun and is spinning with a moderate projected rotational velocity of 65 km/s.[7] It is radiating 20[7] times the luminosity of the Sun from its photosphere at an effective temperature of 8,718 K.[9] It displays an infrared excess, suggesting a debris disk is orbiting the star with a mean separation of 82.96 AU and temperature of 60 K.[13] The system is a source of X-ray emission,[12] which is most likely coming from the 14th[3] magnitude companion.[12]

There are additional visual companions: component C with magnitude 11.5 lies at an angular separation of 64″ from the primary,[14] while component D, has magnitude 14.8 and separation 24".[15]

This star was once considered part of the obsolete constellation Taurus Poniatovii, the brightest star in it. After the International Astronomical Union officially recognised constellations, it was placed in Ophiuchus.[16]

  1. ^ a b c d e f Cite error: The named reference vanLeeuwen2007 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference Ducati2002 was invoked but never defined (see the help page).
  3. ^ a b c d e Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Gray2003 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Kharchenko2007 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference XHIP was invoked but never defined (see the help page).
  7. ^ a b c d e f g Cite error: The named reference Zorec2012 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference AllendePrieto was invoked but never defined (see the help page).
  9. ^ a b c d e Cite error: The named reference David2015 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Cowley1969 was invoked but never defined (see the help page).
  12. ^ a b c Cite error: The named reference DeRosa2011 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference gaspar2016 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Renson was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference WDS was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference ridpath was invoked but never defined (see the help page).