Alpha Ophiuchi
Star in the constellation Ophiuchus / From Wikipedia, the free encyclopedia
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Alpha Ophiuchi (α Ophiuchi, abbreviated Alpha Oph, α Oph), also named Rasalhague /ˈræsəlheɪɡ/,[11][12] is a binary star and the brightest star in the constellation of Ophiuchus.
Quick Facts Observation data Epoch J2000 Equinox J2000, Constellation ...
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Ophiuchus |
Right ascension | 17h 34m 56.06945s[1] |
Declination | +12° 33′ 36.1346″[1] |
Apparent magnitude (V) | 2.07[2] |
Characteristics | |
Spectral type | A5IVnn[3] / K5–7 V[4] |
U−B color index | +0.10[2] |
B−V color index | +0.15[2] |
Astrometry | |
Radial velocity (Rv) | +12.6[5] km/s |
Proper motion (μ) | RA: 108.07[1] mas/yr Dec.: -221.57[1] mas/yr |
Parallax (π) | 67.13 ± 1.06 mas[1] |
Distance | 48.6 ± 0.8 ly (14.9 ± 0.2 pc) |
Absolute magnitude (MV) | +1.248[6] |
Orbit[4] | |
Period (P) | 3,148.4 days |
Semi-major axis (a) | 427+20 −13 mas |
Eccentricity (e) | 0.92±0.03 |
Inclination (i) | 125+6 −9° |
Longitude of the node (Ω) | 232±9° |
Periastron epoch (T) | 2,452,888±53 JD |
Argument of periastron (ω) (secondary) | 162±14° |
Details | |
α Oph A | |
Mass | 2.40+0.23 −0.37[4] M☉ |
Radius | 2.6[7] R☉ |
Luminosity | 25.1–25.6[8] L☉ |
Surface gravity (log g) | 3.91[7] cgs |
Temperature | 7,880–8,050[8] K |
Rotational velocity (v sin i) | 240[8] km/s |
Age | 0.77±0.03[9] Gyr |
α Oph B | |
Mass | 0.85+0.06 −0.04[4] M☉ |
Other designations | |
Database references | |
SIMBAD | data |
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