Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Hydra |
Right ascension | 10h 10m 35.27667s [1] |
Declination | −12° 21′ 14.6938″ [1] |
Apparent magnitude (V) | 3.61 [2] |
Characteristics | |
Spectral type | K0IIIbCN0.5 [3] |
U−B color index | 0.92 [4] |
B−V color index | 1.00 [4] |
Astrometry | |
Radial velocity (Rv) | 19.4 [5] km/s |
Proper motion (μ) |
RA: -201.27
[1]
mas/
yr Dec.: -99.63 [1] mas/ yr |
Parallax (π) | 30.0232 ± 0.6973 mas [6] |
Distance | 109 ± 3
ly (33.3 ± 0.8 pc) |
Absolute magnitude (MV) | +0.92 [7] |
Orbit [8] | |
Period (P) | 1585.8 days |
Semi-major axis (a) | 16.79 mas |
Eccentricity (e) | 0.138 |
Inclination (i) | 79.49° |
Longitude of the node (Ω) | 249.62° |
Periastron epoch (T) | 2448664.3906 |
Argument of periastron (ω) (secondary) | 238.9° |
Details | |
λ Hya A | |
Mass | 1-2 [9] M☉ |
Radius | 9.7 [9] R☉ |
Luminosity | 39.8 [9] L☉ |
Surface gravity (log g) | 2.64 [9] cgs |
Temperature | 4,656 [9] K |
Metallicity [Fe/H] | +0.25 [10] dex |
Rotational velocity (v sin i) | 1.9 [11] km/s |
Other designations | |
Database references | |
SIMBAD | data |
λ Hydrae, Latinised as Lambda Hydrae, is a spectroscopic binary [12] star in the constellation Hydra. Its apparent magnitude is 3.61 Located around 33.3 parsecs (109 ly) distant. The spiral galaxy NGC 3145 is only 7.8 ′ away to the southwest.
The primary is an orange giant of spectral type K0IIICN+1, [13] a star that has used up its core hydrogen, left the main sequence, and expanded into a giant. It is considered to be a red clump giant, a cool horizontal branch star that is burning helium in its core. [14]
λ Hydrae has two visual companions, components B and C, 11th and 13th magnitude stars respectively 71 ″ and 111″ away. [15]
Observation data Epoch J2000 Equinox J2000 | |
---|---|
Constellation | Hydra |
Right ascension | 10h 10m 35.27667s [1] |
Declination | −12° 21′ 14.6938″ [1] |
Apparent magnitude (V) | 3.61 [2] |
Characteristics | |
Spectral type | K0IIIbCN0.5 [3] |
U−B color index | 0.92 [4] |
B−V color index | 1.00 [4] |
Astrometry | |
Radial velocity (Rv) | 19.4 [5] km/s |
Proper motion (μ) |
RA: -201.27
[1]
mas/
yr Dec.: -99.63 [1] mas/ yr |
Parallax (π) | 30.0232 ± 0.6973 mas [6] |
Distance | 109 ± 3
ly (33.3 ± 0.8 pc) |
Absolute magnitude (MV) | +0.92 [7] |
Orbit [8] | |
Period (P) | 1585.8 days |
Semi-major axis (a) | 16.79 mas |
Eccentricity (e) | 0.138 |
Inclination (i) | 79.49° |
Longitude of the node (Ω) | 249.62° |
Periastron epoch (T) | 2448664.3906 |
Argument of periastron (ω) (secondary) | 238.9° |
Details | |
λ Hya A | |
Mass | 1-2 [9] M☉ |
Radius | 9.7 [9] R☉ |
Luminosity | 39.8 [9] L☉ |
Surface gravity (log g) | 2.64 [9] cgs |
Temperature | 4,656 [9] K |
Metallicity [Fe/H] | +0.25 [10] dex |
Rotational velocity (v sin i) | 1.9 [11] km/s |
Other designations | |
Database references | |
SIMBAD | data |
λ Hydrae, Latinised as Lambda Hydrae, is a spectroscopic binary [12] star in the constellation Hydra. Its apparent magnitude is 3.61 Located around 33.3 parsecs (109 ly) distant. The spiral galaxy NGC 3145 is only 7.8 ′ away to the southwest.
The primary is an orange giant of spectral type K0IIICN+1, [13] a star that has used up its core hydrogen, left the main sequence, and expanded into a giant. It is considered to be a red clump giant, a cool horizontal branch star that is burning helium in its core. [14]
λ Hydrae has two visual companions, components B and C, 11th and 13th magnitude stars respectively 71 ″ and 111″ away. [15]