Upsilon Ophiuchi
  | |
| 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] |
| Astrometry | |
| Radial velocity (Rv) | −30.60[5] km/s |
| Proper motion (μ) | RA: −97.526[2] mas/yr Dec.: −33.97[2] mas/yr |
| Parallax (π) | 25.0819±0.2300 mas[2] |
| Distance | 130 ± 1 ly (39.9 ± 0.4 pc) |
| Absolute magnitude (MV) | 1.75[1] |
| Orbit[6] | |
| Primary | Aa1 |
| Companion | Aa2 |
| 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] | |
| Primary | Aa |
| Companion | Ab |
| 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 | |
| Aa1 | |
| Mass | 1.83[8] M☉ |
| Radius | 1.6[8][a] R☉ |
| Luminosity | 16.56[1] L☉ |
| Surface gravity (log g) | 4.45[9] cgs |
| Temperature | 8,364[9] K |
| Metallicity [Fe/H] | +0.14[1] dex |
| Rotational velocity (v sin i) | 44[10] km/s |
| Age | 50[8] Myr |
| Aa2 | |
| Mass | 1.47[8] M☉ |
| Radius | 1.4[8][a] R☉ |
| Age | 50[8] Myr |
| Ab1 | |
| Mass | 0.82[8] M☉ |
| Radius | 0.86[8][a] R☉ |
| Age | 45[8] Myr |
| Ab2 | |
| Mass | 0.70[8] M☉ |
| Radius | 0.69[8][a] R☉ |
| Age | 45[8] Myr |
| 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 | |
| SIMBAD | data |
| Aa1 | |||||||||||
| Period = 27.s d | |||||||||||
| Ab2 | |||||||||||
| Period = 82.8 yr | |||||||||||
| Ab1 | |||||||||||
| Sep = 0.06 au | |||||||||||
| Ab2 | |||||||||||
Hierarchy of orbits[8]
Upsilon Ophiuchi is a quadruple star 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. The distance to this system is approximately 130 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 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 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
[edit | edit source]- ^ a b c d Calculated using angular diameters (0.37, 0.33, 0.20 and 0.16 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
[edit | edit source]- ^ a b c d e Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Vizier catalog entry
- ^ a b c d e 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.
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).Vizier catalog entry
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b c d e f g h i j k l m n o Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ a b Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value). Vizier catalog entry
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
- ^ Lua error in Module:Citation/CS1/Configuration at line 2172: attempt to index field '?' (a nil value).
