Direct detection of extrasolar planets

Has been achieved. Previously, the existence of planets around other suns has been inferred from subtle modulation of the starlight, either as a planet gravitationally tugged its star or as a star’s light decreased when a planet eclipsed it. Now, two groups have used the Spitzer Space Telescope to directly record infrared light from eclipsing planets. planets—with the prosaic names of HD 209458b (153 light years away) and TrES-1 (489 light years away)—have circular orbits a tenth the size of Mercury’s, which makes the Jupiter-sized planets hot enough to be viewed by Spitzer. Unlike observations of other eclipsing systems, these detections relied on the planet being hidden behind the star. When the starlight was subtracted from the light of the complete system, only the planet’s IR emission remained. (D. Deming et al., Nature 434, 740, 2005 http://dx.doi.org/10.1038/nature03507 ; D. Charbonneau et al. , Astrophys. J., in press.)