Rho Ophiuchi
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Ophiuchus |
| Right ascension | 16h 25m 35.11766s |
| Declination | −23° 26′ 49.8150″ |
| Apparent magnitude (V) | 4.63 |
| Characteristics | |
| ρ Oph AB | |
| Spectral type | B2/3V + B2V |
| U−B color index | −0.56 |
| B−V color index | +0.24 |
| Astrometry | |
| ρ Oph AB | |
| Radial velocity (Rv) | −14.6±1.5 km/s |
| Proper motion (μ) | RA: −5.53 mas/yr Dec.: −21.74 mas/yr |
| Parallax (π) | 7.19±0.13 mas |
| Distance | 451±12 ly (138.2±3.6 pc) |
| Absolute magnitude (MV) | −2.5±0.3 |
| Orbit | |
| Primary | ρ Oph Aa |
| Companion | ρ Oph Ab |
| Period (P) | 87.831±0.010 days |
| Semi-major axis (a) | 0.995±0.026 AU |
| Eccentricity (e) | 0.17931±0.00017 |
| Inclination (i) | 71.348±0.020° |
| Longitude of the node (Ω) | 303.385±0.034° |
| Periastron epoch (T) | 60101.11 RJD |
| Argument of periastron (ω) (secondary) | 4.80±0.24° |
| Semi-amplitude (K1) (primary) | 55.5±3.6 km/s |
| Semi-amplitude (K2) (secondary) | 65.7±3.6 km/s |
| Orbit | |
| Primary | ρ Oph A |
| Companion | ρ Oph B |
| Period (P) | 2,398±326 years |
| Semi-major axis (a) | 4.25±0.79″ |
| Eccentricity (e) | 0.675±0.322 |
| Inclination (i) | 135.3±6.0° |
| Longitude of the node (Ω) | 77.5±13.5° |
| Periastron epoch (T) | B 2327±343 |
| Argument of periastron (ω) (secondary) | 226.1±15.3° |
| Orbit | |
| Primary | ρ Oph D |
| Companion | ρ Oph E |
| Period (P) | 675.5±32.5 years |
| Semi-major axis (a) | 1.01±0.15″ |
| Eccentricity (e) | 0.707±0.112 |
| Inclination (i) | 134.8±2.7° |
| Longitude of the node (Ω) | 152.7±4.6° |
| Periastron epoch (T) | B 2008.6±34.2 |
| Argument of periastron (ω) (secondary) | 260.4±1.1° |
| Details | |
| ρ Oph Aa | |
| Mass | 9.21±0.79 M☉ |
| Radius | 4.2±0.3 R☉ |
| Luminosity | 4,270+980 −800 L☉ |
| Surface gravity (log g) | 4.25±0.25 cgs |
| Temperature | 23,000±1,000 K |
| Rotation | 1.205 days |
| Rotational velocity (v sin i) | 206±5 km/s |
| Age | 15±6 Myr |
| ρ Oph Ab | |
| Mass | 7.79±0.70 M☉ |
| Radius | 3.1±0.2 R☉ |
| Luminosity | 1,000+400 −290 L☉ |
| Surface gravity (log g) | 4.25±0.25 cgs |
| Temperature | 19,000±1,000 K |
| Rotational velocity (v sin i) | 227±5 km/s |
| Age | 15±6 Myr |
| ρ Oph B | |
| Mass | 8 M☉ |
| ρ Oph C | |
| Mass | 5 M☉ |
| ρ Oph D | |
| Mass | 3.06 M☉ |
| ρ Oph E | |
| Mass | 1.97 M☉ |
| Other designations | |
| ρ Oph, 5 Oph, WDS J16256-2327 | |
| ρ Oph AB: CD−23°12861, HIP 80473 | |
| ρ Oph A: HD 147933, HR 6112, SAO 184382 | |
| ρ Oph B: HD 147934, HR 6113, SAO 184381 | |
| ρ Oph C: CD−23°12862, HIP 80474, SAO 184383 | |
| Database references | |
| SIMBAD | ρ Oph |
| ρ Oph A | |
| ρ Oph B | |
| ρ Oph C | |
| ρ Oph D/E | |
Rho Ophiuchi (ρ Ophiuchi) is a multiple star system in the constellation Ophiuchus. The central system has an apparent magnitude of 4.63. Based on the central system's parallax, it is located about 450 light-years distant. The other stars in the system are slightly farther away.