The HAT-P-4 system contains 1 exoplanet. It is located 1045.17 light years away from the solar system.
| Mass | 0.56 solar masses |
| Radius | 1.62 solar radiae |
| Temperature | 5860 kelvin |
| Stellar Metallicity | 0.24 decimal exponent |
| Age | 3.9 billion years |
At more than 50 Earth masses, HAT-P-4 b is a gas giant, a planet whose mass is mostly made up of hydrogen and helium, like Jupiter and Saturn.
| Mass | 213.255 Earth masses |
| Density | 0.403 grams per cubic centimeter |
| Radius | 14.280 Earth radiae |
| Semi-major Axis | 0.04438 AU |
| Eccentricity | 0 |
| Orbital Period | 3.057 days |
| Discovery Method | Transit |
| Discovery Facility | HATNet |
| Discovery Telescope | Canon 200mm f/1.8L |
| Discovery Instrument | 2K CCD Sensor |
| Discovery Date | 2007-11 |
| Reference | Kovacs et al. 2007 |