A team of astronomers from the University of Bern studied data from the European Space Agency (ESA) CHEOPS space telescope and found that “one of the most extreme exoplanets in the universe” is so hot that it can vaporize iron.
The “ultra-hot Jupiter” is called WASP-189b and it is located about 322 light-years away from Earth. It was first discovered in 2018 and the CHEOPS telescope has been studying its orbit, temperature, and size. In fact, WASP-189b was the first exoplanet that the telescope studied after being launched late last year.
The data revealed that the planet is one and a half times the size of Jupiter and it completes a full orbit around its host star in just three days. Additionally, they were able to determine that the planet’s surface temperature is a whopping 5,792 degrees Fahrenheit (3,200 degrees Celsius) – hot enough to vaporize iron. Another interesting fact is that the star, which is called HD 133112, is the hottest star that’s known to have a planetary system.
Only one side of WASP-189b is permanently facing its star, whereas in our Solar System, the gas giants Jupiter and Saturn rotate so different areas of the planets face our sun. There aren’t any clouds on the dayside of WASP-189b because of the extreme heat so it’s probably not able to reflect anything.
As for the star, astronomers found some pretty interesting information about HD 133112, “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 outwards at its equator,” said Willy Benz, who is from the University of Bern and a co-author of the study. It is over 3,600 degrees Fahrenheit hotter than our sun and is quite a bit bigger which makes it appear blue in color because of the extreme heat. (An artist’s impression of what WASP-189b would look like orbiting the star can be seen here.)
Since the planet has an inclined orbit, it is believed that it was formed much further away from the star than where it is located today and was somehow pushed towards the star. “As we measured such a tilt with CHEOPS, this suggests that WASP-189 b has undergone such interactions in the past,” explained Monika Lendl, who is from the University of Geneva and the lead author of the study. Their study was published in the journal Astronomy and Astrophysics where it can be read in full.
For its first project, CHEOPS has certainly done a fantastic job and there are thousands more exoplanets that are waiting to be studied. “This first result from CHEOPS is hugely exciting: it is early definitive evidence that the mission is living up to its promise in terms of precision and performance,” stated Kate Isaak who is a CHEOPS project scientist at ESA.