DTM’s Sara Seager and visiting investigator Jeremy Richardson are two of the co-authors on a new paper published this week in Nature discussing data gathered by NASA’s Spitzer Space Telescope which are the first to show light emitted by an object agreed to be an extrasolar planet. Taking advantage of the infrared capabilities of Spitzer, scientists were able to pinpoint the light of the planet, HD 209458b, given that at infrared wavelengths the light of the planet is enhanced as compared with that of its nearby star because of the heat being emitted by the planet.

Scientists were able to isolate the light emitted by HD 209458b by collecting the total infrared radiation from both the star and the planet, and then, when the planet’s orbit carried it behind the star, they measured the total infrared radiation of the star alone. The difference between these two conditions reveals the radiation emitted only by the planet. The data discussed in the paper reveal that the planet’s temperature exceeds 1,000 Kelvin, confirming theories developed by many scientists dealing with extrasolar planets. Through additional observations, scientists hope to characterize these hot-Jupiters further, including gathering information about the planets’ composition and possibly their winds. (See associated press release.)

The paper’s findings, along with parallel results for a second hot-Jupiter, TrES-1 (studied by a group of scientists at the Harvard-Smithsonian Center for Astrophyics), were discussed in a NASA press conference on March 22.