71 Ophiuchi
Giant star in the constellation of Ophiuchus
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71 Ophiuchi is a single[8] star in the equatorial constellation of Ophiuchus. It is visible to the naked eye as a faint, yellow-hued point of light with an apparent visual magnitude of 4.64.[2] The star is located approximately 273 light years away from the Sun based on parallax,[9] and is moving closer with a radial velocity of −3 km/s.[5]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ophiuchus |
| Right ascension | 18h 07m 18.35888s[1] |
| Declination | +08° 44′ 01.9181″[1] |
| Apparent magnitude (V) | 4.64[2] |
| Characteristics | |
| Spectral type | G8III[3] |
| U−B color index | +0.73[4] |
| B−V color index | +0.97[4] |
| Astrometry | |
| Radial velocity (Rv) | −3.00±0.09[5] km/s |
| Proper motion (μ) | RA: +9.857[1] mas/yr Dec.: +29.770[1] mas/yr |
| Parallax (π) | 13.1352±0.1891 mas[1] |
| Distance | 248 ± 4 ly (76 ± 1 pc) |
| Absolute magnitude (MV) | 0.03[2] |
| Details[6] | |
| Mass | 2.87±0.09 M☉ |
| Radius | 12.55+0.27 −0.34[1] R☉ |
| Luminosity | 88.8±1.5[1] L☉ |
| Surface gravity (log g) | 3.00±0.02 cgs |
| Temperature | 5,001+70 −52[1] K |
| Metallicity [Fe/H] | 0.10±0.01 dex |
| Rotational velocity (v sin i) | 0.32±0.45 km/s |
| Age | 400±30 Myr |
| Other designations | |
| 71 Oph, BD+08°3582, GC 24693, HD 165760, HIP 88765, HR 6770, SAO 123140[7] | |
| Database references | |
| SIMBAD | data |
At the estimated age of 400 million years,[6] this is an aging giant star with a stellar classification of G8III,[3] having exhausted the supply of hydrogen at its core and expanded to around 13[1] times the Sun's radius. It is a red clump giant,[10] which means it is on the horizontal branch and is generating energy through helium fusion at its core. The star has 2.9 times the mass of the Sun and is radiating 89 times the Sun's luminosity from its swollen photosphere at an effective temperature of 5,001 K.[6]