HR 4458

HR 4458
Observation data
Epoch J2000      Equinox J2000
Constellation Hydra
Right ascension 11h 34m 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]
Distance31.13 ± 0.02 ly
(9.544 ± 0.005 pc)
Absolute magnitude (MV)6.05[6]
Details
HR 4458 A
Radius0.84[7] R☉
Luminosity (bolometric)0.368[8] L☉
Surface gravity (log g)4.59[9] cgs
Temperature5,241[9] K
Metallicity [Fe/H]–0.37[9] dex
Rotational velocity (v sin i)6.79[10] km/s
Age4.6–5.8[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
SIMBADdata
ARICNSdata

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.[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 separation of 162.5 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]

  1. ^ a b c d e Cite error: The named reference GaiaDR2 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference aaa34 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference aj132_1_161 was invoked but never defined (see the help page).
  4. ^ a b c Cite error: The named reference mnras435_3_2077 was invoked but never defined (see the help page).
  5. ^ a b Cite error: The named reference apjss141 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference Holmberg2009 was invoked but never defined (see the help page).
  7. ^ a b Cite error: The named reference ajss183 was invoked but never defined (see the help page).
  8. ^ a b c Cite error: The named reference aa555_A11 was invoked but never defined (see the help page).
  9. ^ a b c d Cite error: The named reference apj756_1_46 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference aaa520_A79 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference apj687 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  13. ^ a b Cite error: The named reference Rodriguez2015 was invoked but never defined (see the help page).