HAT P 3b

HAT-P-3b is an extrasolar planet that orbits the star HAT-P-3 approximately 457 light-years away in the constellation of Ursa Major. It was discovered by the HATNet Project via the transit method and confirmed with Doppler spectrography, so both its mass and radius are known quite precisely; based on these figures it is predicted that the planet has about 75 Earth masses worth of heavy elements in its core, making it similar to the planet HD 149026b.

In 2013, this planet was photometrically observed by Spitzer space telescope which characterized its near-zero eccentricity and low albedo.