ONE of the first exoplanets to be imaged directly is not the plain Jane it seemed. Instead, it may be a rocky planet covered with lava.
Hubble Space Telescope images from 2004 and 2006 revealed a Jupiter-like dot around the star Fomalhaut. But new observations by NASA's Spitzer Space Telescope find nothing at the infrared wavelengths where a Jupiter-sized planet should be brightest.
Spitzer is not sensitive enough to detect a smaller planet, says Markus Janson of Princeton University. He says a rocky planet a few times Earth's mass could explain the observations if impactors melted its surface, making it visibly brighter than expected for its size (arxiv.org/abs/1201.4388).
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