Upsilon Ophiuchi

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Upsilon Ophiuchi
Location of υ Ophiuchi (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation
Ophiuchus[1]
Right ascension 16h 27m 48.17331s[2]
Declination −08° 22′ 18.4156″[2]
Apparent magnitude (V) 4.62[1]
Characteristics
Spectral type kA2hA5VmA5[3]
U−B color index +0.06[4]
B−V color index +0.16[4]
Distance
130 ± 1 ly
(39.9 ± 0.4 pc)
Absolute magnitude (MV)1.75[1]
Semi-amplitude
(K1)
(primary)		34.9±0.3 km/s
Semi-amplitude (K2)
(secondary)		41.1±0.3 km/s
Argument of periastron
(ω)
(secondary)		177.9±7.4°
Details
Aa1
Myr
Ab1
Myr
HR 6129, SAO 141187, CCDM J16278-0822AB, WDS J16278-0822[11]
Database references
SIMBADdata
Aa1
Period = 27.s d
Ab2
Period = 82.8 yr
Ab1
Sep = 0.06 au
Ab2

Hierarchy of orbits[8]

Upsilon Ophiuchi is a

light years based on parallax. It is drifting closer with a radial velocity
of −30.6 km/s.

The variable radial velocity of the brighter component was first observed by

Am stars.[3] The fainter component has an 82.8 year orbit with the brighter pair at an eccentricity of 0.45,[7] and is itself binary, making the system a quadruple.[8] The system is a source for X-ray emission.[12]

This system forms part of the Upsilon Ophiuchi cluster, a small group of six stars which share similar kinematics and are spread over about eight degrees. The two brightest stars, apart from Upsilon Ophiuchi itself, are sometimes listed as components B and C: B is HD 148300, and C is HD 144660.[8] Both are 9th-magnitude K-class dwarfs.[13]

Notes

  1. ^
    milliarcseconds
    ) and a distance of 39.9 parsecs via the equation R/R☉ = (107.5 • 𝜃 • d)/1000, where 𝜃 is the angular diameter and d is the distance.

References

  1. ^
    S2CID 119257644. Vizier catalog entry
  2. ^
    S2CID 244398875
    . Gaia DR3 record for this source at VizieR.
  3. ^
    doi:10.1086/192182
    .
  4. ^
    Bibcode:2014JAVSO..42..443M.Vizier catalog entry
  5. LCCN 54001336. {{cite journal}}: ISBN / Date incompatibility (help
    )
  6. ^
    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. ^
    ISSN 2515-5172
    .
  9. ^
    S2CID 33401607. Vizier catalog entry
  10. Bibcode:1995yCat.5050....0H
    .
  11. ^ "ups Oph", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2019-10-21.
  12. doi:10.1051/0004-6361:20077429
  13. Bibcode:2001KFNT...17..409K
    .
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