HAT-P-2b
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HAT-P-2b is an extrasolar planet detected by the Harvard-Smithsonian Center for Astrophysics in May 2007. It orbits a class F star, (bigger and hotter than the Sun), located about 440 light-years away in the constellation Hercules. Every 5 days 15 hours, it crosses directly in front of the star as viewed from Earth.[1]
| Planet | Jupiter |
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The planet's mass has been estimated to be more than 8 times that of Jupiter while its radius is 1.18 times that of Jupiter it would be a bit smaller if it was located at Jupiter's distance. Its size is due to the intense heating of its parent star causing slight bloating to the outer layers of its atmosphere. This indicates that the planet's mean density is similar to that of Earth and its surface gravity is approximately 15 times that on Earth. The orbit is very eccentric, ranging from 3.1 million miles to 9.6 million miles from the star; if Earth's orbit were as eccentric its distance from the sun would vary from a distance equivalent to Mercury to a distance equivalent to Mars.[1]
It has been suggested that there is a second outer planet perturbing HAT-P-2b. This has not so far been proved or disproved.[1]
References
- ^ a b c "Astronomers find super-massive planet" (Press release). Harvard-Smithsonian Center for Astrophysics. May 2, 2007.