Rare Discovery: Astronomers Spot Two New Inflated 'Hot Jupiters'

A team of astronomers have recently detected two new "hot Jupiters," called such because of their likeness to Jupiter, according to a study published on by the Cornell University Library. The team, led by Joel Hartman of Princeton University, discovered that the "hot Jupiters" are less massive than our own Jupiter, with a slightly larger radius.

Called HAT-P-65b and HAT-P-66b, the exoplanets are likened to giant gas planets that have similar characteristics with Jupiter. HAT-P-65b is only half the mass of Jupiter while HAT-P-66b is about 78 percent of Jupiter's mass. Their orbital periods are less than 10 days.

The newly detected "hot Jupiters" have larger diameters than the usual, concluding that these exoplanets are inflated. They were detected by the Hungarian-made Automated Telescope Network (HATNet), where the team performed follow-up spectrographic and photometric observations to verify these planet's physical characteristics.

Phys Org reports that HAT-P-65b and HAT-P-66b have two distant stars that orbits them, which are nearing the end of their "main sequence lifetimes." HAT-P-65b's star is already 5.46 billion years old while HAT-P-66b's star is said to be estimated at 4.66 billion years old.

As mentioned earlier, the exoplanets have larger diameter than usual. They are even larger than our own giant gas planets, with HAT-P65b radius at almost 1.9 percent of Jupiter's radii while HAT-P-66b diameter is around 1.6 of Jupiter.

What could be the reasons of its inflation? There are two possibilities being studied: the deposition of energy from host stars and the restrained cooling of the planet.

The paper also suggested that in order to determine which of the possibilities can be true, there is a need to have a large sample of similar inflated exoplanets. This will also help to identify its pattern. However, judging with previous records of similar inflated planets, the deposition theory is more possible.