and size measurements of an unusual giant planet
German Aerospace Center (DLR) | 2020 Sep 28
Initial measurements made by the European CHaracterising ExOPlanet Satellite (CHEOPS) space telescope indicate that the giant planet, WASP-189b, located 326 light years from Earth, glows as hot as a small star as it orbits its central star at high speed on an unusual orbit that takes it close to the star's poles. At 3200 degrees Celsius, it is one of the hottest bodies of the over 4000 known exoplanets. ...
"The planet WASP-189b was detected in 2018. Because of its unusual orbit close to its central star, we studied it with CHEOPS very early on," explains Szilárd Csizmadia ... "The precise measurements made with CHEOPS have now revealed its extraordinary characteristics: it is an ultra-hot planet, almost 1.6 times the diameter of Jupiter, and its orbit around its star is strangely inclined." ...
CHEOPS measures the dips in the observed light intensity of a star when an orbiting planet passes in front of it with great accuracy. In addition to measuring a primary transit event of WASP-189b, when the planet passes across the line of sight between the observer and the star, CHEOPS was also able to measure the much smaller dip during the secondary signal when the planet disappears behind the star with respect to the observer. These extremely precise measurements of such an occultation allows the temperature of the planet to be derived. It was determined that WASP-189b has a surface temperature of approximately 3200 degrees Celsius, hotter than almost any other exoplanet known to date. At such temperatures, all rocks and metals melt and become gaseous. By way of comparison, the Sun has a surface temperature of almost 6000 degrees Celsius, but some small M dwarf stars have temperatures well below 3000 degrees Celsius. ...
CHEOPS Describes One of the Most Extreme Planets in the Universe
University of Bern | University of Geneva | 2020 Sep 28
The Hot Dayside and Asymmetric Transit of WASP-189b Seen by CHEOPS ~ Monika Lendl et al
- Astronomy & Astrophysics (accepted 17 Sep 2020) DOI: 10.1051/0004-6361/202038677 (pdf)