HR 4458
HR 4458 is a binary star system in the equatorial constellation of Hydra. 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. It is moving closer to the Earth with a heliocentric radial velocity of −22 km/s.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Hydra |
| Right ascension | 11h 34m 29.48628s |
| Declination | –32° 49′ 52.8199″ |
| Apparent magnitude (V) | 5.97 + 15 |
| Characteristics | |
| Spectral type | K0 V + DC8 |
| U−B color index | 0.325 |
| B−V color index | 0.80 |
| V−R color index | 0.44 |
| R−I color index | 0.40 |
| Astrometry | |
| Radial velocity (Rv) | –22.21 km/s |
| Proper motion (μ) | RA: –670.120 mas/yr Dec.: +822.228 mas/yr |
| Parallax (π) | 104.7828 ± 0.0518 mas |
| Distance | 31.13 ± 0.02 ly (9.544 ± 0.005 pc) |
| Absolute magnitude (MV) | 6.05 |
| Details | |
| HR 4458 A | |
| Radius | 0.84 R☉ |
| Luminosity (bolometric) | 0.368 L☉ |
| Surface gravity (log g) | 4.59 cgs |
| Temperature | 5,241 K |
| Metallicity [Fe/H] | –0.37 dex |
| Rotational velocity (v sin i) | 6.79 km/s |
| Age | 4.6–5.8 Gyr |
| Other designations | |
| WD 1132-325: VB 04 | |
| Database references | |
| SIMBAD | data |
| ARICNS | data |
The primary component is K-type main-sequence star with a stellar classification of K0 V. It is around five billion years old with 84% of the Sun's radius. The star is radiating 37% of the Sun's luminosity from its photosphere at an effective temperature of 5,241 K. It has been examined for the presence of an infrared excess, but none was detected.
There is a common proper motion companion at an angular separation of 16.2″, corresponding to a projected separation of 162.5 AU. This is a white dwarf star with a classification of DC8. The orbital period of the pair is estimated as 1,110 years.