70 Ophiuchi
70 Ophiuchi is a binary star system located 16.6 light years away from the Earth. It is in the constellation Ophiuchus. At magnitude 4 it appears as a dim star visible to the unaided eye away from city lights.
| Observation data Epoch J2000 Equinox | |
|---|---|
| Constellation | Ophiuchus |
| 70 Ophiuchi | |
| Right ascension | 18h 05m 27.285s |
| Declination | +02° 29′ 00.36″ |
| Apparent magnitude (V) | 4.00 - 4.03 |
| A | |
| Right ascension | 18h 05m 27.371s |
| Declination | +02° 29′ 59.32″ |
| Apparent magnitude (V) | 4.13 |
| B | |
| Right ascension | 18h 05m 27.462s |
| Declination | +02° 29′ 56.22″ |
| Apparent magnitude (V) | 6.07 |
| Characteristics | |
| Spectral type | K0V + K4V |
| Apparent magnitude (B) | 4.97/7.26 |
| Apparent magnitude (R) | 3.6/5.6 |
| U−B color index | +0.69 |
| B−V color index | +0.84/+1.19 |
| Variable type | BY Dra or RS CVn |
| Astrometry | |
| 70 Oph A | |
| Radial velocity (Rv) | −6.87 km/s |
| Proper motion (μ) | RA: 206.525±0.246 mas/yr Dec.: −1107.492±0.164 mas/yr |
| Parallax (π) | 195.5674 ± 0.1964 mas |
| Distance | 16.68 ± 0.02 ly (5.113 ± 0.005 pc) |
| Absolute magnitude (MV) | +5.49 |
| 70 Oph B | |
| Proper motion (μ) | RA: 333.292±0.264 mas/yr Dec.: −1068.354±0.215 mas/yr |
| Parallax (π) | 195.2166 ± 0.1012 mas |
| Distance | 16.707 ± 0.009 ly (5.123 ± 0.003 pc) |
| Orbit | |
| Period (P) | 88.38±0.017 yr |
| Semi-major axis (a) | 4.554±0.0052″ |
| Eccentricity (e) | 0.4992±0.00039 |
| Inclination (i) | 121.16±0.078° |
| Longitude of the node (Ω) | 302.12±0.097° |
| Periastron epoch (T) | 1895.94 |
| Argument of periastron (ω) (secondary) | 14.0±0.14° |
| Details | |
| 70 Oph A | |
| Mass | 0.90 ± 0.04 M☉ |
| Radius | 0.91 ± 0.03 R☉ |
| Luminosity (bolometric) | 0.59 ± 0.02 L☉ |
| Surface gravity (log g) | 4.5 cgs |
| Temperature | 5,300 K |
| Metallicity [Fe/H] | +0.04 dex |
| Rotation | 19.7 days |
| Age | 1.9 Gyr |
| 70 Oph B | |
| Mass | 0.70 ± 0.07 M☉ |
| Luminosity (bolometric) | 0.13 ± 0.03 L☉ |
| Temperature | 4,350 ± 150 K |
| Other designations | |
| 70 Oph A: LHS 458 | |
| 70 Oph B: LHS 459 | |
| Database references | |
| SIMBAD | The system |
| A | |
| B | |
| Exoplanet Archive | data |
| ARICNS | data |
70 Location of 70 Ophiuchi in the constellation Ophiuchus | |
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