An international team of astronomers have found the largest known planet in the Hercules constellation. The exoplanet was discovered by a team working on the Transatlantic Exoplanet Survey (TrES) and is called TrES-4.
The planet is a huge gas giant that is about 70% larger than our Jupiter:
It is so big, in fact, that its size is difficult to explain using current theories about superheated giant planets.
"We continue to be surprised by how relatively large these giant planets can be," says Francis O'Donovan, a graduate student in astronomy at the California Institute of Technology (Caltech) which operates one of the TrES telescopes.
"But if we can explain the sizes of these bloated planets in their harsh environments, it may help us better understand our own Solar System planets and their formation."
Its density of 0.2 grams per cubic centimetre is so low that the planet would, in theory, float on water.
By definition, a transiting planet passes directly between the Earth and the star, blocking some of the star's light and causing a slight drop in its brightness.
"TrES-4 blocks off about 1% of the light of the star as it passes in front of it," said Dr Mandushev.
"With our telescopes and observing techniques, we can measure this tiny drop in the star's brightness and deduce the presence of a planet there."