HD 5388

HD 5388 is a single^[9] star in the southern constellation of Phoenix. It has the Gould designation 78 G. Phoenicis,^[10] while HD 5388 is the star's Henry Draper Catalogue identifier. This object has a yellow-white hue and is too faint to be readily visible to average human eyesight, having an apparent visual magnitude of 6.73.^[3] It is located at a distance of 173 light-years from the Sun based on parallax, and is drifting further away with a radial velocity of +39 km/s.^[2]

This object is an ordinary F-type main-sequence star with a stellar classification of F6V,^[3] indicating that it is generating energy through core hydrogen fusion. It is not chromospherically active and its metal content is half as much as the Sun. The star is larger and more massive than the Sun,^[3] and radiates 4.8^[6] times the Sun's luminosity from its photosphere at an effective temperature of 6297 K.^[6]

In 2009, a substellar object (HD 5388 b) was detected in orbit around the star using the HARPS instrument at La Silla Observatory. Its minimum mass is consistent with a gas giant planet, and it has an elliptical orbit with a period of 2.13 years.^[3] Later astrometric observations suggested that this object is a massive brown dwarf in a nearly face-on orbit rather than a planet,^[11][12] but a more recent astrometric study in 2026 found a much smaller true mass, again consistent with a planet.^[13]