Gliese 436 b
Gliese 436 b ( also GJ 436 b ) is an extrasolar planet that orbits the red dwarf star Gliese 436. He is one of the smallest known exoplanets, and possibly a so-called "hot Neptune ". Gliese 436 b was discovered by Geoffrey Marcy and R. Paul Butler in 2004 by measuring the radial velocity of the star.
Properties
The planet orbits its star at a distance of only 0.03 AU ( 4.3 million miles) every 2 days, 15 hours and 27 minutes on a train with an eccentricity of 0.15, its mass is around 0.072 Jupiter masses. Using the Spitzer Space Telescope, the diameter of Gliese 436 b could be determined relatively accurately to 54,000 km (slightly more than that of Neptune) to a transit of the planet. In conjunction with major planetary models, these data suggest a structure similar close to that of Neptune.