CHEOPS Data Reveals WASP-189b One Of The Most Extreme Planets In The Universe

Eddie Gonzales Jr. – MessageToEagle.com – Using data from the space telescope CHEOPS (CHaracterising ExOPlanet Satellite), researchers have revealed details of the exoplanet WASP-189b, one of the most extreme planets known.

WASP-189b is an exoplanet orbiting the star HD 133112, one of the hottest stars known to have a planetary system. Image credit: ESA

“The WASP-189 system is 322 light-years away and located in the constellation Libra (the weighing scales),” explains Monika Lendl, lead author of the study from the University of Geneva, and member of the National Center of Competence in Research PlanetS.

“WASP-189b is especially interesting because it is a gas giant that orbits very close to its host star. It takes less than three days for it to circle its star, and it is 20 times closer to the star than Earth is to the Sun,” Monika Lendl says.

The planet is more than 1.5 times as large as Jupiter, the largest planet of the solar system.

Planetary objects like WASP-189b are very exotic:

“They have a permanent day side, which is always exposed to the light of the star, and, accordingly, a permanent night side.” This means that its climate is completely different from that of the gas giants Jupiter and Saturn in our solar system.

“Based on the observations using CHEOPS, we estimate the temperature of WASP-189b to be 3,200 degrees Celsius. Planets like WASP-189b are called “ultra-hot Jupiters. Iron melts at such a high temperature, and even becomes gaseous. This object is one of the most extreme planets we know so far,” said Lendl.

“We cannot see the planet itself as it is too far away and too close to its host star, so we have to rely on indirect methods,” explains Lendl. For this, CHEOPS uses highly precise brightness measurements: When a planet passes in front of its star as seen from Earth, the star seems fainter for a short time. This phenomenon is called a transit.

“Because the exoplanet WASP-189b is so close to its star, its dayside is so bright that we can even measure the ‘missing’ light when the planet passes behind its star; this is called an occultation,

We have observed several such occultations of WASP-189b with CHEOPS. It appears that the planet does not reflect a lot of starlight. Instead, most of the starlight gets absorbed by the planet, heating it up and making it shine.”

The researchers believe that the planet is not very reflective because there are no clouds present on its dayside. “This is not surprising, as theoretical models tell us that clouds cannot form at such high temperatures,” says Lendl.

“We also found that the transit of the gas giant in front of its star is asymmetrical. This happens when the star possesses brighter and darker zones on its surface. Thanks to CHEOPS data, we can conclude that the star itself rotates so quickly that its shape is no longer spherical, but ellipsoidal. The star is being pulled outward at its equator,” Willy Benz, professor of astrophysics at the University of Bern, said.

The star around which WASP-189b orbits is very different from the sun.

Paper

Written by Eddie Gonzales Jr. – MessageToEagle.com Staff