HAT-P-5b is an extrasolar planet orbiting the star HAT-P-5, more than 1,100 light-years away, in the constellation Lyra. It was discovered through the transit method in 2007. It is the fifth planet detected by the HATNet Project.

The planet is a typical hot Jupiter, with 106% of the mass and 125% of jupiter’s radius (since the inclination of the system is known, the actual mass of the planet has been calculated). It has 66% of the density of water.

The planet orbits its star at 4% of Earth’s orbital distance, in just under three days per revolution. This keeps the surface and atmosphere of the planet at very high temperatures (calculated at about 1200°C, if not considered albedo3), which could explain its large radius, and such low density.



Observations of HAT-P-5b

Collaborative projects