Iota Ophiuchi
Star in the constellation Ophiuchus
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ι Ophiuchi, Latinized as Iota Ophiuchi, is a single[11] star in the equatorial constellation of Ophiuchus, positioned near the constellation border with Hercules. It makes a naked-eye double with nearby Kappa Ophiuchi,[12] appearing as a faint, blue-white hued star with an apparent visual magnitude of 4.39.[2] The star is approximately 245 light years from the Sun based on parallax,[1] but is drifting closer with a radial velocity of −19 km/s.[6]
 | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ophiuchus |
| Right ascension | 16h 54m 00.47151s[1] |
| Declination | +10° 09′ 55.2982″[1] |
| Apparent magnitude (V) | 4.39[2] |
| Characteristics | |
| Evolutionary stage | main sequence[3] |
| Spectral type | B8V[4] |
| U−B color index | −0.32[5] |
| B−V color index | −0.08[5] |
| Astrometry | |
| Radial velocity (Rv) | −19.0±1.6[6] km/s |
| Proper motion (μ) | RA: −53.80[1] mas/yr Dec.: −34.04[1] mas/yr |
| Parallax (π) | 13.30±0.22 mas[1] |
| Distance | 245 ± 4 ly (75 ± 1 pc) |
| Absolute magnitude (MV) | 0.01[2] |
| Details | |
| Mass | 3.14±0.03[3] M☉ |
| Radius | 2.8[7] R☉ |
| Luminosity | 141+6 −5[3] L☉ |
| Surface gravity (log g) | 4.03[8] cgs |
| Temperature | 11,220±78[3] K |
| Metallicity [Fe/H] | +0.09[8] dex |
| Rotational velocity (v sin i) | 124[3] km/s |
| Age | 217[9] Myr |
| Other designations | |
| ι Oph, 25 Oph, BD+10°3092, FK5 1442, GC 22775, HD 152614, HIP 82673, HR 6281, SAO 102458[10] | |
| Database references | |
| SIMBAD | data |
This object is a B-type main-sequence star with a stellar classification of B8V.[4] It is an estimated 217[9] million years old with a moderately high rate of spin, showing a projected rotational velocity of 124 km/s.[3] The star has 3.1[3] times the mass of the Sun and around 2.8[7] times the Sun's radius. Iota Ophiuchi is radiating 141[3] times the luminosity of the Sun from its photosphere at an effective temperature of 11,220 K.[3] It displays an infrared excess, suggesting the presence of circumstellar material.[13]