The planet HAT- P- 32b has more than twice the radius of Jupiter, yet is only the same mass. It orbits its star more than a factor of ten closer than Mercury's orbit around the Sun. Which is the most plausible explanation for its large size?
A)The hydrogen and helium gas compressed under their own gravity.
B)The mass measurement is mistaken, and it is actually about 10 times more massive than Jupiter.
C)It is made of elements other than hydrogen and helium which do not compress under their own gravity.
D)Planets that are close to a star are heated up and therefore larger.

Question

Quizplus · Accepted Answer

Planets in close proximity to their stars receive a significant amount of stellar radiation, which can cause them to heat up and expand. This heating effect can lead to a larger radius, especially for gas giants like HAT-P-32b, which are primarily composed of hydrogen and helium that can expand when heated. This explains why HAT-P-32b, despite having a similar mass to Jupiter, has a much larger radius.

The Planet HAT- P- 32b Has More Than Twice the Radius