Tuesday 11 June 2013

The atmosphere of Wasp 12b.

Wasp-12b is a super-Jovian Hot Jupiter type planet (a planet larger than Jupiter orbiting very close to its parent star) 871 light years from Earth in the constellation of Auriga. It orbits Wasp-12A, a G-type yellow dwarf star slightly bigger and hotter than our sun (1.35 × the Sun's mass, with a surface temperature of 6300 K, as opposed to 5770 K for our sun), every 26 hours at a distance of 0.229 AU (2.29 % of the distance at which the Earth orbit's the Sun more than ten times as close to its star as Mercury). Wasp-12b is 1.39 as massive as Jupiter but has 28.3 times its volume, being inflated by the heat of the star, with an average surface temperature of 2525 K. Wasp-12b is probably elliptical in shape, and tidally locked, with one face (end) pointing permanently to the star. This face of the planet would reach temperatures in excess of 3000 K, hot enough for the atmosphere to slowly boil away into space. The material lost in this way probably forms an accretionary disk about the star, which will slowly be drawing mass from the planet.

An artist's impression of Wasp 12b. NASA/JPL/Caltech.

In a paper published on the arXiv database at Cornell University Library on 7 May 2013, a team of scientists led by Kevin Stevenson of the Department of Astronomy and Astrophysics at the University of Chicago describe the results of a spectrographic study Wasp 12b by the Spitzer Space Telescope.

This study concludes that the atmosphere of Wasp 12b is probably dark and opaque. Stevenson et al. suggest that the atmosphere of Wasp 12b is either rich in Oxygen with Titanium Oxide, Vanadium Oxide and water forming major components, or rich in Carbon, containing substantial concentrations of Titanium Hydride, Methane and Hydrogen Cyanide.

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