Weird Exoplanets Cheops Investigated in Its First Year

Illustration of CHEOPS, ESA’s first exoplanet mission ESA / ATG Medialab

This week marks the one-year anniversary of the launch of CHEOPS, the exoplanet investigation satellite of the European Space Agency. CHEOPS studies known exoplanets discovered by other missions and examines them in more detail to obtain new information about these distant worlds. Here’s what it discovered in its first year:

Blurred stars

The first image CHEOPS took in February of this year was not a planet but a star – HD 70843, 150 light-years away. The telescope took an intentionally blurred image of this particularly bright star to verify that its brightness was detected correctly and that everything was working well.

CHEOPS also introduced another star, HD 88111, which does not harbor any known exoplanets but was useful as a test. That’s because CHEOPS recognize exoplanets by looking at stars and waiting for planets to pass in front of them, which is known as transit. By observing the star’s eclipse by a tiny amount, scientists can infer the presence of an exoplanet and calculate properties such as size and orbital time.

A wispy pouf

Artist's impression of the star HD 93396 and its hot Jupiter planet KELT-11b.Artist’s impression of the star HD 93396 and its hot Jupiter planet KELT-11b. THE

After confirming that the instruments were working well, CHEOPS discovered its first exoplanet in April of this year. It looked at the star HD 93396, located 320 light years away and around which a planet called KELT-11b orbits. KELT-11b is a large gas giant about a third larger than Jupiter, but only a fifth of its mass. This makes it one of the “swollen planets” that have been discovered so far.

CHEOPS was able to observe an eight-hour transit of the planet and measure its size more accurately than any other instrument before, fixing its diameter at 181,600 km with an uncertainty of only 4,300 km.

Scorching hot

Artist's impression of WASP-189Artist’s impression of WASP-189 b THE

In September of this year, CHEOPS investigated a “hot Jupiter” named WASP-189b, which turned out to be one of the most extreme planets ever found. It is so close to its star that a year there is only 2.7 days, with its orbit being twenty times closer to the star than the earth is to the sun. Not only that, its host star WASP-189 is 2,000 degrees hotter than the sun, which is so incredibly hot that it seems to glow blue.

This makes WASP-189 b one of the few known planets orbiting such a hot and bright star. The researchers estimate that temperatures on the planet would be a scorching 3,200 degrees Celsius, which is hot enough not only to melt metals but also to turn them into gas. It also orbits at an unusual incline, and goes over the poles of the star rather than its equator.

A dramatic evasive maneuver

CHEOPS also had close contact in October this year when it had to avoid a piece of space debris. If the debris had collided with the satellite, it could have completely destroyed it, according to Willy Benz, head of the CHEOPS consortium. Fortunately, CHEOPS was able to get out of the way and avoid the incoming debris.

With this exciting first year, CHEOPS will study hundreds of known exoplanets, gather more detailed information about them and learn new things about these strange, distant worlds over the next few years.

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