Astronomers tend to get excited by pinpricks of light. And perhaps today they have more reason than usual to celebrate the pixels that Paul Kalas at the University of California, Berkeley, and pals have found in one of the Hubble Space Telescope’s images.
These pixels, they say, represent the first optical image of a planet orbiting another star. The star in question is Fomalhaut in the southern constellation of Piscis Austrinus and one of the brightest in the sky.
Kalas and co say the planet is about three times the mass of Jupiter orbiting at a rather distant 119 AU. By comparison, Neptune orbits at around 30 AU so this is going to be one cold body.
That’s impressive work that has had significant press coverage but let’s put it in perspective.
Last year, the infrared Spitzer Space Telescope photographed HD 189733b, a Jupiter-sized gaseous planet orbiting a yellow dwarf in the constellation of Vulpecula. It even produced a heat map of the surface showing, unsurprisingly, that the planet is warmer at the equator than at the poles. But the map of HD 189733b got almost no coverage. And images of various “hot Jupiters” have been around for perhaps a decade or so.
I guess Hubble just has a better PR team.
Ref: arxiv.org/abs/0811.1994: Optical Images of an Exosolar Planet 25 Light Years from Earth∗