"Using" Spitzer telescope, astronomers unravel secrets of Strange ‘hot Jupiter’ planets

Astronomers continue to unlock secrets of strange exoplanets.

Sometimes it’s hard to think about the other planets outside of our solar system because so much is unknown. While we know that other planets exist, we don’t always know every detail. But we are certainly getting closer. Scientists have discovered more than 800 so-called “exoplanets” throughout the universe. These exoplanets are large gas planets known to orbit stars beyond our sun so closely that they are known as “hot Jupiters” or “roasters.”

Now, with the help of NASA’s Spitzer Space Telescope, researchers are beginning to understand what lies beneath the blistering gases. The telescope is allowing scientists to discover not only the differing climates of these exoplanets, but also other characteristics like temperature profiles, chemistries and densities as well.

“The hot Jupiters are beasts to handle. They are not fitting neatly into our models and are more diverse than we thought,” said Nikole Lewis of the Massachusetts Institute of Technology, Cambridge, lead author of a new Spitzer paper in the Astrophysical Journal examining one such hot Jupiter called HAT-P-2b. “We are just starting to put together the puzzle pieces of what’s happening with these planets, and we still don’t know what the final picture will be.”

Swiss astronomers detected the first exoplanet, called 51 Pegasi b, in 1995 using a technique to measure the wobble of star caused by the tug of a planet’s gravity. Due to the size and weight of hot Jupiters, this strategy—the radial velocity technique –allowed scientists to find dozens of these planets. Although scientists initially concluded that these blistering gas giants were common to the universe, they soon found out that they were in fact relatively rare.

As a result, the Spitzer was developed in 2005, becoming the first telescope to detect an exoplanet based off of the light it emits. Scientists have used the telescope to monitor hot Jupiters as they orbit around a star. By observing the planet’s orbit, researchers are able to create global climate maps, alluding to changes in atmospheric temperatures. This enables scientists to piece together clues about the planet’s composition and climate.

“When Spitzer launched in 2003, we had no idea it would prove to be a giant in the field of exoplanet science,” said Michael Werner, the Spitzer project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, California. “Now, we’re moving farther into the field of comparative planetary science, where we can look at these objects as a class, and not just as individuals.”

Data collected by the telescope has created a completely different perspective from planet to planet. Scientists are finding some planets to be covered in haze, while others are completely clear.

“These planets are much hotter and more dynamic than our own Jupiter, which is sluggish by comparison. Strong winds are churning material up from below, and the chemistry is always changing,” Lewis said.