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Gamma Hydrae
Star in the constellation Hydra / From Wikipedia, the free encyclopedia
Gamma Hydrae (γ Hya, γ Hydrae) is a binary star in the equatorial constellation of Hydra. It has an apparent visual magnitude of 3.0,[2] placing it second in brightness among the members of this generally faint constellation. Based upon parallax measurements made during the Hipparcos mission, this star is at a distance of around 133.8 light-years (41.0 parsecs) from Earth.[1]
Quick Facts Constellation, Right ascension ...
Observation data Epoch J2000.0 Equinox J2000.0 | |
---|---|
Constellation | Hydra |
Right ascension | 13h 18m 55.29719s[1] |
Declination | –23° 10′ 17.4514″[1] |
Apparent magnitude (V) | +2.993[2] |
Characteristics | |
Spectral type | G8 III[3] |
U−B color index | +0.645[2] |
B−V color index | +0.920[2] |
Astrometry | |
Radial velocity (Rv) | –5.4[4] km/s |
Proper motion (μ) | RA: +68.99[1] mas/yr Dec.: –41.85[1] mas/yr |
Parallax (π) | 24.37 ± 0.15 mas[1] |
Distance | 133.8 ± 0.8 ly (41.0 ± 0.3 pc) |
Absolute magnitude (MV) | –0.15[3] |
Details | |
A | |
Mass | 2.94[3] M☉ |
Radius | 16±3[5] R☉ |
Luminosity | 115[3] L☉ |
Surface gravity (log g) | 3.02[6] cgs |
Temperature | 5,087[6] K |
Metallicity [Fe/H] | –0.06[6] dex |
Rotational velocity (v sin i) | 8[7] km/s |
Age | 372[3] Myr |
B | |
Mass | 0.61+0.12 −0.14[8] M☉ |
Orbit[8] | |
Primary | A |
Companion | B |
Semi-major axis (a) | 67.5±0.6 or 159±7 AU |
Other designations | |
Database references | |
SIMBAD | data |
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