HD 213240

HD 213240 is a possible binary star system in the constellation Grus. It has an apparent visual magnitude of 6.81, which lies below the limit of visibility for normal human sight. The system is located at a distance of 133.5 light years from the Sun based on parallax. The primary has an absolute magnitude of 3.77.

This is an ordinary G-type main-sequence star with a stellar classification of G0/G1V. It is a metal-rich star with an age that has been calculated as being anywhere from 2.7 to 4.6 billion years. The star has 1.6 times the mass of the Sun and 1.56 times the Sun's radius. It is spinning with a projected rotational velocity of 3.5 km/s. The star is radiating 2.69 times the luminosity of the Sun from its photosphere at an effective temperature of 5,921 K.

A red dwarf companion star was detected in 2005 with a projected separation of 3,898 AU.

Planetary system
The Geneva extrasolar planet search team discovered a planet orbiting this star in 2001. Since this planet was discovered by radial velocity, only its minimum mass was initially known, and there was a 5% chance of it being massive enough to be a brown dwarf. In 2023, the inclination and true mass of HD 213240 b were determined via astrometry, confirming its planetary nature.