Skip to main content

Scientists find distant planet that’s so hot iron would evaporate there

Europe’s CHEOPS satellite, launched in December last year, has uncovered details about its first exoplanet: An extreme world that is one of the hottest planets ever studied, where even metals like iron would evaporate and turn into gas.

The planet, named WASP-189 b, is of a type called an ultra-hot Jupiter, because it is a gas giant like Jupiter and it is (you guessed it) ultra-hot.

The planet orbits 20 times closer to its star than Earth does to the sun, zipping around in a year which lasts just 2.7 days. Not only does it orbit extremely close to its star, but that star itself is also incredibly hot, being over 2,000 degrees Celsius hotter than the sun. In fact, the star is so hot that it would appear to glow blue.

It was the extreme brightness of the star which allows astronomers to spot the planet, as lead author Monika Lendl of the University of Geneva, Switzerland explained: “As the planet is so bright, there is actually a noticeable dip in the light we see coming from the system as it briefly slips out of view. We used this to measure the planet’s brightness and constrain its temperature to a scorching 3,200 degrees C.”

Artist impression of WASP-189
Artist impression of exoplanet WASP-189b orbiting its host star. The system was observed by ESA’s exoplanet mission Cheops to determine key characteristics. For example, the host star is larger and more than 2000 degrees hotter than our own Sun, and so appears to glow blue. ESA

The whole system is hot, bright, and unusual. “Only a handful of planets are known to exist around stars this hot, and this system is by far the brightest,” Lendl said. “WASP-189b is also the brightest hot Jupiter that we can observe as it passes in front of or behind its star, making the whole system really intriguing.”

As well as the hot planet, the star in this system has some interesting properties which grabbed the researchers’ attention. “We also saw that the star itself is interesting — it’s not perfectly round, but larger and cooler at its equator than at the poles, making the poles of the star appear brighter,” Lendl said. “It’s spinning around so fast that it’s being pulled outwards at its equator! Adding to this asymmetry is the fact that WASP-189 b’s orbit is inclined; it doesn’t travel around the equator, but passes close to the star’s poles.”

The information about the tilted orbit of the planet was of particular interest as it suggests that at some point in its history, it was influenced by other planets or another star, pushing it into its position closer to its star. This could help to unravel the mystery of how these extremely hot gas giants form.

The findings are published in the journal Astronomy & Astrophysics.

Editors' Recommendations

Georgina Torbet
Georgina is the Digital Trends space writer, covering human space exploration, planetary science, and cosmology. She…
Hubble spies on 25 hot Jupiters to learn about their atmospheres
Archival observations of 25 hot Jupiters by the NASA/ESA Hubble Space Telescope.

In the last decade, we've become remarkably good at identifying exoplanets, or planets outside our solar system. In fact, we recently passed an impressive milestone of over 5,000 confirmed exoplanets discovered. However, most of these detections tell us little about the planets we've identified -- typically only their distance from their host star, and their mass or size.

The next big step in exoplanet research is learning more about these planets, and in particular what their atmospheres are like. This is one of the major aims of the James Webb Space Telescope when it's ready for science this summer, but in the meantime, researchers are getting creative to answer these questions. Recently, astronomers using data from the Hubble Space Telescope have investigated 25 exoplanets to find out about their atmospheres.

Read more
Hints of a planet in the habitable zone of a dead star
exoplanet habitable zone dead star white dwarf planetary debris

When you think of searching for habitable planets, you probably think about looking for Earth-like planets orbiting sun-like stars. But the range of possibly habitable planets is larger than that, and astronomers recently discovered indications of a planet in the habitable zone of a dead star.

When stars eventually run out of fuel, they first grow and cool to become red dwarfs, before losing the last of their hydrogen and shrinking and cooling further to become a white dwarf. This is what will eventually happen to our sun, as well as 95% of other stars. It's rare to find planets orbiting these white dwarfs, but recent research found indications of one such planet in the white dwarf's narrow habitable zone for the first time.

Read more
Astronomers spot a new planet orbiting our neighboring star
This artist’s impression shows a close-up view of Proxima d, a planet candidate recently found orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System.

At just over four light-years away, the low-mass star Proxima Centauri is practically next door to us, cosmically speaking. It is known to host two exoplanets, but recent research using the European Southern Observatory’s Very Large Telescope (ESO’s VLT) has shown that these two planets may have a baby brother, in the form of one of the lightest exoplanets ever found.

The newly discovered planet, called Proxima d, orbits extremely close to its star at just 2.5 million miles away -- less than one-tenth of the distance between Mercury and the sun. It is so close that it takes just five days to complete an orbit, meaning it is too close to be in the habitable zone (where liquid water could be present on its surface).

Read more