Xi Ophiuchi

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Xi Ophiuchi
Location of ξ Ophiuchi (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ophiuchus
Right ascension 17h 21m 00.37452s[1]
Declination −21° 06′ 46.5710″[1]
Apparent magnitude (V) 4.39[2]
Characteristics
Spectral type F2V[3]
U−B color index −0.06[4]
B−V color index +0.41[4]
Astrometry
Radial velocity (Rv)−8.73±0.12[1] km/s
Proper motion (μ) RA: +265.543 mas/yr[1]
Dec.: −202.584 mas/yr[1]
Parallax (π)57.0820±0.1851 mas[1]
Distance57.1 ± 0.2 ly
(17.52 ± 0.06 pc)
Absolute magnitude (MV)3.19[2]
Details[5]
A
Mass1.30 M☉
Radius1.59±0.06 R☉
Luminosity4.429±0.035[6] L☉
Surface gravity (log g)4.15±0.10 cgs
Temperature6,611±80 K
Metallicity [Fe/H]−0.27±0.07 dex
Rotational velocity (v sin i)20.2±0.7 km/s
Age916[7] Myr
Other designations
ξ Oph, 40 Oph, BD−20°4731, FK5 917, GC 23423, GJ 670, HD 156897, HIP 84893, HR 6445, SAO 185296, CCDM J17210-2107AB, WDS J17210-2107AB, LTT 6908[8]
Database references
SIMBADA
B

ξ Oph, Latinized as Xi Ophiuchi, is a visual binary star[9] system in the equatorial constellation of Ophiuchus.[2] It has a yellow-white hue and is faintly visible to the naked eye with a combined apparent visual magnitude of 4.39.[2] The system is located approximately 57.1 light-years (17.5 parsecs) away from the Sun based on parallax, but is drifting closer with a radial velocity of -9 km/s.[1]

The magnitude 4.40[10] primary, designated component A, is an ordinary F-type main-sequence star with a stellar classification of F2V.[3] It is 916[7] million years old and is rotating with a projected rotational velocity of 20 km/s. The star has 1.3 times the mass of the Sun and 1.6 times the Sun's radius.[5] It is radiating 4.4[6] times the luminosity of the Sun from its photosphere at an effective temperature of 6,611 K.[5]

The system is a source of X-ray emission.[11] The orbiting companion, component B, is a magnitude 8.9 star at an angular separation of 4.1″ along a position angle of 26° from the primary, as of 2016. A magnitude 10.8 visual companion, component C, lies at a separation of 10.8″, as of 2004.[10]

According to Richard H. Allen's Star Names: Their Lore and Meaning (1899), ξ Oph together with θ 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".[12] The name Aggia for this star appears in a 1971 NASA list of star names[13] and in a 2023 list of target stars for the Habitable Worlds Observatory.[14] As of June 2025, it does not appear in the IAU Catalog of Star Names.[15]

References

[edit | edit source]
  1. ^ a b c d e f Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Gaia DR3 record for this source at VizieR.
  2. ^ a b c d Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Vizier catalog entry
  3. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  4. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).Vizier catalog entry
  5. ^ a b c Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  6. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Gaia DR2 record for this source at VizieR.
  7. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Vizier catalog entry
  8. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  9. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  10. ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Vizier catalog entry
  11. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  12. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  13. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  14. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
  15. ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
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