| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hydra |
| Right ascension | 11h34m 29.48628s[1] |
| Declination | –32° 49′ 52.8199″[1] |
| Apparent magnitude (V) | 5.97[2] + 15 |
| Characteristics | |
| Spectral type | K0 V[3] + DC8[4] |
| U−B color index | 0.325[2] |
| B−V color index | 0.80[2] |
| V−R color index | 0.44 |
| R−I color index | 0.40 |
| Astrometry | |
| Radial velocity (Rv) | –22.21[5] km/s |
| Proper motion (μ) | RA: –670.120[1] mas/yr Dec.: +822.228[1] mas/yr |
| Parallax (π) | 104.7828 ± 0.0518 mas[1] |
| Distance | 31.13 ± 0.02 ly (9.544 ± 0.005 pc) |
| Absolute magnitude (MV) | 6.05[6] |
| Details | |
| HR 4458 A | |
| Radius | 0.84[7] R☉ |
| Luminosity (bolometric) | 0.368[8] L☉ |
| Surface gravity (log g) | 4.59[9] cgs |
| Temperature | 5,241[9] K |
| Metallicity [Fe/H] | –0.37[9] dex |
| Rotational velocity (v sin i) | 6.79[10] km/s |
| Age | 4.6–5.8[11] Gyr |
| Other designations | |
289 G. Hydrae, CD−32°8179, GJ 432, HD 100623, HIP 56452, HR 4458, SAO 202583, LHS 308, LTT 4280[12] | |
| WD 1132-325: VB 04 | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
HR 4458 is a binary star system in the equatorial constellationofHydra. It has the Gould designation 289 G. Hydrae; HR 4458 is the Bright Star Catalogue designation. At a distance of 31.13 light years, it is the closest star system to the Solar System within this constellation. This object is visible to the naked eye as a dim, orange-hued star with an apparent visual magnitude of 5.97.[2] It is moving closer to the Earth with a heliocentric radial velocity of −22 km/s.[5]
The primary component is K-type main-sequence star with a stellar classification of K0 V.[3] It is around five[11] billion years old with 84%[7] of the Sun's radius. The star is radiating 37%[8] of the Sun's luminosity from its photosphere at an effective temperature of 5,241 K.[9] It has been examined for the presence of an infrared excess, but none was detected.[8]
There is a common proper motion companion at an angular separation of 16.2″,[4] corresponding to a projected separationof162.5 AU.[13] This is a white dwarf star with a classification of DC8.[4] The orbital period of the pair is estimated as 1,110 years.[13]
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