Upsilon Ophiuchi

Upsilon Ophiuchi
Location of υ Ophiuchi (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Ophiuchus
Right ascension 16h 27m 48.18720s[1]
Declination −8° 22′ 18.2245″[1]
Apparent magnitude (V) 4.62[2]
Characteristics
Spectral type kA2hA5VmA5[3]
U−B color index +0.06[4]
B−V color index +0.16[4]
Astrometry
Radial velocity (Rv)−30.60[5] km/s
Proper motion (μ) RA: −67.49[1] mas/yr
Dec.: −11.75[1] mas/yr
Parallax (π)24.42 ± 0.91 mas[1]
Distance134 ± 5 ly
(41 ± 2 pc)
Absolute magnitude (MV)1.75[2]
Orbit[6]
PrimaryAa
CompanionAb
Period (P)27.218±0.0005 d
Semi-major axis (a)≥ 0.0583 AU
Eccentricity (e)0.744±0.002
Periastron epoch (T)2,438,914.84±0.01 JD
Argument of periastron (ω)
(secondary)
333.7±0.7°
Semi-amplitude (K1)
(primary)
34.9±0.3 km/s
Semi-amplitude (K2)
(secondary)
41.1±0.3 km/s
Orbit[7]
PrimaryA
CompanionB
Period (P)82.8±1.4 yr
Semi-major axis (a)0.79±0.03
Eccentricity (e)0.45±0.03
Inclination (i)31.2±5.7°
Longitude of the node (Ω)86.8±6.9°
Periastron epoch (T)B 1994.1±1.0
Argument of periastron (ω)
(secondary)
177.9±7.4°
Details
Mass1.94[8] M
Radius1.9[8] R
Luminosity16.56[2] L
Surface gravity (log g)4.45[9] cgs
Temperature8,364[9] K
Metallicity [Fe/H]+0.14[2] dex
Rotational velocity (v sin i)44[10] km/s
Other designations
Alkarab, υ Oph, 3 Ophiuchi, BD−08°4243, FK5 3299, GC 22134, HD 148367, HIP 80628, HR 6129, SAO 141187, CCDM J16278-0822AB, WDS J16278-0822[11]
Database references
SIMBADdata

Upsilon Ophiuchi is a triple star[12] system in the equatorial constellation of Ophiuchus. It has a white hue and is faintly visible to the naked eye with an apparent visual magnitude of 4.62.[2] The distance to this system is approximately 134 light years based on parallax.[1] It is drifting closer with a radial velocity of −30.6 km/s.[5]

The variable radial velocity of the brighter component was first observed by H. A. Abt in 1961. It is a double-lined spectroscopic binary system with an orbital period of 27.2 days and an eccentricity of 0.74.[6] They have a combined magnitude of 4.71. Both components are similar stars with a combined stellar classification of kA2hA5VmA5, and one or both are Am stars.[3] The third component has an 82.8 year orbit with the inner pair at an eccentricity of 0.45.[7] The system is a source for X-ray emission.[13]

  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 e Cite error: The named reference XHIP was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference abt1995 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Mallama2014 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference Wilson1953 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Gutman1965 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference ORB6 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference AllendePrieto was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference David2015 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Hoffleit1991 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Eggleton2008 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Schröder2007 was invoked but never defined (see the help page).