Exoplanet Observations By NASA's Spitzer Space Telescope Have Scientists Both Stunned And Confused

With the help of NASA’s Sptizer Space Telescope, researchers are beginning to dissect an exotic class of planets known as hot Jupiters or roasters, due to their tight orbits around their stars.

Among the many discoveries being made, however, are just how varied these gas giants' climates are, according to a release from the Jet Propulsion Laboratory.

“The hot Jupiters are beasts to handle,” said Nikole Lewis of the Massachusetts Institute of Technology and lead author of a new Spitzer paper analyzing one such hot Jupiter. “They are not fitting neatly into our models and are more diverse than we thought.”

These planets were the first exoplanets ever discovered and were first uncovered in 1995 by Swiss astronomers who used a technique in which they measured the wobble of the star caused by the tug of a planet. Because these hot Jupiters are both heavy and orbit around the stars so quickly, they were easiest to find using this strategy and dozens of discoveries of roasters soon followed.

In fact, scientists found so many that researchers began to think they represented a dominant planet type; however, new research, including evidence from NASA’s Kepler space telescope, show they are really quite rare.

In 2005, Spitzer became the first telescope to detect light emitted by an exoplanet, which also happened to be a hot Jupiter. It then watched as the planet disappeared behind the star in an event called a secondary eclipse.

Since then, Spitzer has probed the atmospheres of dozens of hot Jupiters, and, in the latest study based on a Spitzer observation, scientists discuss how the infrared telescope watched one planet for six days as it crossed in front of its star, slipped behind it and then reappeared on the other side in a comet-like eccentric orbit.

“It’s as if nature has given us a perfect lab experiment with this system,” said Heather Knutson, a co-author of the new paper at the California institute of Technology. “Because the planet’s distance to the sun changes, we can watch how fast it takes to heat up and cool down. It’s as though we’re turning the heat knob up on our planet and watching what happens.”

The study is also the first to use multiple wavelengths of infrared light instead of just one, thus enabling scientists to view different layers of the planet.

In all, Lewis’ team left the observation with 2 million data points to map out. As they do so, according to Nick Cowan of Northwestern University, “Theories are being shot down right and left. Right now, it’s like the wild, wild west.”