HD 22781
# HD 22781

HD 22781, is a single star about 106 light-years away. It is a K-type main-sequence star. The star’s age is poorly constrained at 4.14±3.63 billion years, but is likely similar to that of the Sun. HD 22781 is heavily depleted in heavy elements, having just 45% of Sun's concentration of iron, yet is comparatively rich in carbon, having 90% of Sun`s abundance.

An imaging survey in 2012 has failed to find any stellar companions, suggesting HD 22781 is a single star.

## Planetary system

In 2011 a transiting superjovian planet or brown dwarf b was detected on an extremely eccentric orbit. It is located just outside of the conservative habitable zone of the parent star. Planets around such metal-poor stars are rare; the only three known similar cases are HD 111232 and HD 181720.

In 2012, a radial velocity data review indicated there are no additional giant planets in the system.

The HD 22781 planetary system :

| Companion (in order from star) | Mass | Semimajor axis (AU) | Orbital period (days) | Eccentricity | Inclination | Radius |
| - | - | - | - | - | - | - |
| b | ≥13.65±0.97 $M_J$ | 1.167±0.039 | 528.07±0.14 | 0.8191±0.0023 | — | — |
