HR 4458 (HD 100623) is a binary star system 31.18light-years away in the equatorial constellation of Hydra. It has the Flamsteed designation 20 Crateris and the Gould designation 289 G. Hydrae; the former refers to the constellation Crater, since Flamsteed numbered the stars of Crater and the central portion of Hydra as a separate constellation from the other parts of Hydra. 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 −22km/s.

The primary component is a K-type main-sequence star with a stellar classification of K0V. It is around fivebillion years old with 90% of the Sun's mass and 84% of the Sun's radius. The star is radiating 37% of the Sun's luminosity from its photosphere at an effective temperature of 5,241K. It has been examined for the presence of an infrared excess, but none was detected.

The secondary, designated VB 4, is a 15th-magnitude white dwarf of class DC8 sharing common proper motion with the primary. The orbital period of the pair is of 1,400 years, albeit with large uncertainty.

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External links

  • . SolStation. Archived from on 2012-10-13.