Giant 'Hot Jupiter' Exoplanet Has Weird Winds That Defy the Laws of Science
A giant, gaseous exoplanet that orbit its host star in less than three days name d CoRot-2b was discovered in 2007.
Planets like this often classified as "hot Jupiters" because of their similar physical properties to Jupiter, were thought to be tied to their parent stars for years. This would mean that the hotter side side of the planet faces the star, while the other side faces space. Scientists had observed strong winds blowing east toward the equator of these planets, which can move their hottest spot slightly east of center.
But CoRot-2b disrupts that theory, as the planet's hottest spot lies to the west of its center.
"We've previously studied nine other hot Jupiter, giant planets orbiting super close to their star. In every case, they have had winds blowing to the east, as theory would predict. But now, nature has thrown us a curveball. On this planet, the wind blows the wrong way. Since it's often the exceptions that prove the rule, we are hoping that studying this planet will help us understand what makes hot Jupiters tick," Nicolas Cowan, an astronomer at McGill University, Canada, and a co-author of a new study, said in a statement.
Since its discovery just over a decade ago, CoRoT-2b continues to intrigue scientists because of its inflated size and the confounding spectrum of light emitted from its surface. This latter question prompted scientists to use the Spitzer's Infrared Array Camera, allowing them to map the planet's surface brightness for the first time by observing the planet completing an orbit around its host star, thus revealing the hot spot was slightly to the west.
Scientists have a few possible theories to explain this westward hotspot.
One is that the planet spins so slowly that one rotation takes longer to complete than a full orbit of its star. This would create winds blowing west instead of east, but would also disprove existing theories about gravitational relationships between planets and stars in such tight orbits. The second theory is that the planet's atmosphere interacts with its magnetic field, thus modifying its winds. If true, it would provide scientists with a rare opportunity to study an exoplanet's magnetic field. The last theory is that large clouds covering the planet's eastern side make it appear darker than it otherwise would. This is the least likely because it would dispute our current understanding of how atmospheric circulation on these exoplanets work in the first place.
"We'll need better data to shed light on the questions raised by our finding," lead study author and McGill PhD student Lisa Dang says. "Fortunately, the James Webb Space Telescope, scheduled to launch next year, should be capable of tackling this problem. Armed with a mirror that has 100 times the collecting power of Spitzer's, it should provide us with exquisite data like never before."
All of this goes to show that there is still much about exoplanets that we simply don't know. The closest Earth-like exoplanet might not be habitable as previously thought, and a newly discovered giant exoplanet with a carbon monoxide atmosphere defied all of our expectations. Among the thousands of exoplanets already discovered, we recently found one about 13 times larger than Jupiter at the center of our galaxy.