HD 114762

HD 114762 is a triple star system approximately 38.2 pc away in the constellation Coma Berenices. It consists of a yellow-white F-type main-sequence star (HD 114762 A) and two red dwarf companions (HD 114762 Ab & HD 114762 B) approximately 0.36 & 130 AU distant. Both are low-metal subdwarfs. Planets around such metal-poor stars are rare (three known cases are HD 22781, HD 111232, and HD 181720). A telescope or strong binoculars are needed to view the primary. HD 114762 had been used by scientists as a "standard star", one whose radial velocity is well established, but with the discovery of the spectroscopic companion HD 114762 Ab its usefulness as a standard has been called into question.

The red dwarf companion is classified as an ultra-cool dwarf, with a spectral type around M9. With a visual magnitude of 15 and separated from the primary by only three arcseconds, it can only be seen with a powerful telescope. It is estimated to be around 10 billion years old, although the properties of such low-mass stars are very similar across a wide range of ages. It is calculated have only 8% of the mass of the Sun, a tenth of its radius, and with a temperature of about $49.63$ it produces less than a thousandth of its luminosity.

Spectroscopic companion
In 1989, a companion object, HD 114762 Ab, was found orbiting HD 114762 A by Latham, et al., using Doppler spectroscopy, but its existence was not confirmed until 1991 by Cochran, et al. Its orbital distance and revolution is similar to that of Mercury, though it has twice the eccentricity. It has a minimum mass of, and thus was originally thought to be a massive exoplanet; however, in 2019, its inclination was determined by Gaia astrometry, giving it a true mass of. This makes it a red dwarf star, or a massive brown dwarf. A 2020 study provided further confirmation of this, and revised the mass upwards to, and in 2022 this mass was revised upwards still further, to , based on Gaia DR3 data and a similar upwards revision to the mass of the primary star.