The HD 156668 system contains 2 exoplanets. It is located 79.36 light years away from the solar system.
| Mass | 0.77 solar masses |
| Radius | 0.72 solar radiae |
| Temperature | 4850 kelvin |
| Stellar Metallicity | 0.05 decimal exponent |
| Age | 8.6 billion years |
With a mass below 5 Earth masses, a density of 3.49, and a semi-major axis of 0.05 astronomical units, HD 156668 b could, potentially, be an ocean world - a planet with no dry land.
| Mass | 4.150 Earth masses |
| Density | 3.490 grams per cubic centimeter |
| Radius | 1.870 Earth radiae |
| Semi-major Axis | 0.05 AU |
| Eccentricity | 0 |
| Orbital Period | 4.646 days |
| Discovery Method | Radial Velocity |
| Discovery Facility | W. M. Keck Observatory |
| Discovery Telescope | 10 m Keck I Telescope |
| Discovery Instrument | HIRES Spectrometer |
| Discovery Date | 2011-01 |
| Reference | Howard et al. 2011 |
At more than 10 Earth masses, HD 156668 c is an ice giant, a planet that is made up mostly of volatiles like water, amonia and methane, and enveloped by a dense hydrogen and helium atmosphere, much like Uranus and Neptune.
| Mass | 31.497 Earth masses |
| Density | 0.737 grams per cubic centimeter |
| Radius | 6.170 Earth radiae |
| Semi-major Axis | 1.57 AU |
| Eccentricity | 0.089 |
| Orbital Period | 811.300 days |
| Discovery Method | Radial Velocity |
| Discovery Facility | Multiple Observatories |
| Discovery Telescope | Multiple Telescopes |
| Discovery Instrument | Multiple Instruments |
| Discovery Date | 2021-07 |
| Reference | Rosenthal et al. 2021 |