  | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hydra[1] |
| Right ascension | 14h 50m 17.30146s[2] |
| Declination | −27° 57′ 37.3385″[2] |
| Apparent magnitude (V) | 4.42[1] |
| Characteristics | |
| Evolutionary stage | red giant branch[3] |
| Spectral type | K2.5 IIIb Fe-1:[4] |
| B−Vcolor index | 1.366±0.050[1] |
| Astrometry | |
| Radial velocity (Rv) | −8.7±1.5[1] km/s |
| Proper motion (μ) | RA: −232.696[2]mas/yr Dec.: −60.118[2]mas/yr |
| Parallax (π) | 11.4440±0.5105 mas[2] |
| Distance | 290 ± 10 ly (87 ± 4 pc) |
| Absolute magnitude (MV) | −0.60[1] |
| Details | |
| Mass | 0.88[3] M☉ |
| Radius | 33.40+0.41 −1.13[2] R☉ |
| Luminosity | 310.19[3] L☉ |
| Surface gravity (log g) | 1.35[3] cgs |
| Temperature | 4,210[3] K |
| Metallicity[Fe/H] | −0.43±0.04[1] dex |
| Rotational velocity (v sin i) | 4.23[5] km/s |
| Age | 8.1[3] Gyr |
| Other designations | |
| Solitaire,E Hya,58 Hya,CD−27°10073,HD 130694,HIP 72571,HR 5526,SAO 182911,LTT 5887[6] | |
| Database references | |
| SIMBAD | data |
58 Hydrae, also namedSolitaire,[7] is a single[8]star in theequatorialconstellation ofHydra, located around 290 light years away from the Sun based onparallax.[2] It has theBayer designationE Hydrae;58 Hydrae is theFlamsteed designation − a later designation of6 Librae.[9] It is visible to the naked eye as a faint, orange-hued star with anapparent visual magnitude of 4.42.[1] This object is moving closer to the Earth with a heliocentricradial velocity of −9 km/s.[1]
This is an aginggiant star with astellar classification ofK2.5 IIIb Fe-1:,[4] most likely (98% chance) on thered giant branch.[3] The suffix notation indicates an underabundance of iron in thespectrum, and some uncertainty about the classification. It is around 8.1 billion years old with 0.88 times themass of the Sun.[3] As a consequence of exhausting the hydrogen at itscore, the star has expanded to 33.4[2] times theSun's radius. It is radiating 310 times theluminosity of the Sun from its swollenphotosphere at aneffective temperature of 4,210 K.[3]
This star was a member of the obsolete constellationTurdus Solitarius, which was named after theRodrigues solitaire, a now extinct species of bird, though in old star charts it was illustrated as ablue rock thrush.[10] TheIAU Working Group on Star Names approved the name Solitaire for this star on 31 October 2024, after the obsolete constellation, and it is now so entered in the IAU Catalog of Star Names.[7]
