| Observation data EpochJ2000.0 EquinoxJ2000.0 (ICRS) | |
|---|---|
| Constellation | Hydra |
| Right ascension | 10h 38m 34.95281s[1] |
| Declination | −16° 52′ 35.6665″[1] |
| Apparent magnitude (V) | 4.90[2] |
| Characteristics | |
| Evolutionary stage | red clump[3] |
| Spectral type | G8 III[4] |
| B−Vcolor index | 0.912[5] |
| Astrometry | |
| Radial velocity (Rv) | +17.45±0.70[6] km/s |
| Proper motion (μ) | RA: −98.92[1]mas/yr Dec.: +25.84[1]mas/yr |
| Parallax (π) | 15.49±0.57 mas[1] |
| Distance | 211 ± 8 ly (65 ± 2 pc) |
| Absolute magnitude (MV) | +0.89[7] |
| Orbit[2] | |
| Period (P) | 1200 d |
| Eccentricity (e) | 0.1 |
| Periastronepoch (T) | 2420760 JD |
| Argument of periastron (ω) (secondary) | 270° |
| Semi-amplitude (K1) (primary) | 4.0 km/s |
| Details | |
| φ3 Hya | |
| Mass | 2.04[4] M☉ |
| Radius | 9[5] R☉ |
| Luminosity | 48[4] L☉ |
| Surface gravity (log g) | 2.95[7] cgs |
| Temperature | 4,952±17[4] K |
| Metallicity [Fe/H] | −0.22±0.12[7] dex |
| Rotational velocity (v sin i) | 3.6[5] km/s |
| Age | 1.17[4] Gyr |
| Other designations | |
| φ3 Hya,BD−16°3100,FK5 2850,HD 92214,HIP 52085,HR 4171,SAO 156122[8] | |
| Database references | |
| SIMBAD | data |
Phi3 Hydrae (φ3 Hya) is abinary star[2] in the equatorialconstellation ofHydra. It originally received theFlamsteed designation of2 Crateris before being placed in the Hydra constellation.[9] Based upon an annualparallax shift of 15.49 mas as seen from Earth, it is located around 211 light years from theSun. It is visible to the naked eye with anapparent visual magnitude of 4.90.[2] It forms a triangle with the fainterφ1 Hydrae andφ2 Hydrae, betweenμ Hydrae andν Hydrae.
This is a single-linedspectroscopic binary star system with anorbital period of about 1,200 days and aneccentricity of 0.1.[2] The primary, component A, is anevolvedG-typegiant star with astellar classification of G8 III.[4] It is ared clump star,[3] which means it is generating energy through thefusion of helium at its core. The star has twice[4] themass of the Sun and has expanded to 9[5] times theSun's radius. It is 1.17[4] billion years old and is radiating 48[4] times thesolar luminosity from itsphotosphere at aneffective temperature of 4,952 K.[4]
