51 Ophiuchi
Star in the constellation Ophiuchus / From Wikipedia, the free encyclopedia
51 Ophiuchi is a single[8] star located approximately 410[1] light years away from the Sun in the equatorial constellation of Ophiuchus, northwest of the center of the Milky Way. It is visible to the naked eye as a faint, blue-white point of light with an apparent visual magnitude of 4.81.[2] The star is moving closer to the Earth with a heliocentric radial velocity of –12 km/s.[4]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Ophiuchus |
Right ascension | 17h 31m 24.95413s[1] |
Declination | −23° 57′ 45.5136″[1] |
Apparent magnitude (V) | 4.81[2] |
Characteristics | |
Spectral type | B9.5IIIe[3] |
U−B color index | –0.06[2] |
B−V color index | +0.00[2] |
Astrometry | |
Radial velocity (Rv) | –12[4] km/s |
Proper motion (μ) | RA: 5.24[1] mas/yr Dec.: −25.72[1] mas/yr |
Parallax (π) | 8.04 ± 0.24 mas[1] |
Distance | 410 ± 10 ly (124 ± 4 pc) |
Details | |
Mass | 3.3±0.1[5] M☉ |
Radius | 5.66±0.23[5] R☉ |
Luminosity | 3.12[6] L☉ |
Temperature | 9,772[6] K |
Metallicity [Fe/H] | –0.25[6] dex |
Rotational velocity (v sin i) | 267 ± 5[7] km/s |
Age | 0.3[8] Myr |
Other designations | |
Database references | |
SIMBAD | data |
This object is notable for being "a rare, nearby example of a young planetary system just entering the last phase of planet formation".[10] There is uncertainty about the stellar classification of this star. It has the nominal classification of B9.5IIIe, a B-type giant star with emission lines. However, it has also been classified as an A0 II-IIIe star and as a Herbig Ae/Be star.[11] 51 Ophiuchi is about 300,000[8] years old with 3.3 times the mass of the Sun and a polar radius 5.7 times the Sun's radius.[5] It is radiating three[6] times the Sun's luminosity from its photosphere at an effective temperature of 9,772 K.[6] The star is spinning rapidly with a projected rotational velocity of 267 km/s,[7] close to the critical rotation rate.[5]