One of the most inflated giant planets found

Astronomers claim to have discovered one of the most inflated giant planets known to date, orbiting a mildly evolved star about 2.4 times larger than our Sun. The exoplanet designated KELT-12b was spotted by a team of researchers led by Daniel Stevens of the Ohio State University in the US.

A giant exoworld that expands in size when its parent star is at the end of its life is called "inflated." This inflation process is very often seen in the so-called "hot Jupiters" - gas giant planets similar in characteristics to the solar system's biggest planet, with orbital periods of less than 10 days.

The astronomers employed the KELT-North telescope at the Winer Observatory in Arizona. While analysing KELT-North data acquired from 2007 to 2013, the scientists identified the initial transit signal of KELT-12b. The team conducted follow-up observations to confirm the planetary nature of this signal.

The newly found alien world is orbiting a mildly evolved, 2 billion-year-old star KELT-12 that is about 2.4 times larger than our Sun and has a mass of about 1.59 solar masses. The planet with an orbital period of five days is slightly less massive than Jupiter, having about 0.95 the mass of the solar system's gas giant, 'Phys.org' reported.

However, its radius is much larger than astronomers have expected - about 1.79 Jupiter radii. This relatively large radius, combined with an extremely low density at a level of just 0.21 grammes per cubic centimetre indicates that KELT-12b is an inflated exoplanet. The scientists said that it is one of the most inflated "hot Jupiters" discovered so far.