Home / Science / A distant blue star is home to one of the most extreme exoplanets known to science

A distant blue star is home to one of the most extreme exoplanets known to science



Artistic impression of the exoplanet WASP-1<div class="e3lan e3lan-in-post1"><script async src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>
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</script></div>89b orbiting its host star, which glows blue.

Artistic impression of the exoplanet WASP-189b orbiting its host star, which glows blue.
Image: ESA

The newly deployed CHEOPS space telescope has completed its first observations of a exoplanet, uncovering some fascinating new details about a superheated Jupiter known as WASP-189b.

Hot Jupiter are Jupiter-like exoplanets located in close proximity to their host stars, hence their name. Ultra-hot Jupiter is basically the same, but, Comets you probably guessed it, they are even hotter. In 2018, astronomers were using the ground-based WASP-South telescope in South Africa detected a boiling Jupiter nicknamed WASP-189b, unlike anything seen before.

Two years later, using the brandspanking-new space telescope Characterizing Exoplanet Satellite (CHEOPS), astronomers have observed this celestial wonder with new eyes, refining what we know about this unusual exoplanet, while affirming the enormous potential of this European space telescope, which has only just begun to do comments last April.

Indeed, CHEOPS, compared to ground-based telescopes, “is simply much more accurate,” Monika Lendl, an astronomer at the University of Geneva and lead author of the new study, explained in an email. “Since CHEOPS observes from space, it does not need to look through the Earth’s atmosphere, and thus the light is not disturbed by the turbulence of the air. “

CHEOPS, a collaboration between the European Space Agency and the Swiss Space Office, is designed exclusively to detect and observe exoplanets, which it does by detecting dips in the brightness of a star, a potential sign of an exoplanet passing by (i.e. the method transit detection). CHEOPS will also study previously detected exoplanets, as in the case of WASP-189b.

“Cheops has a unique ‘follow-up’ role to play in studying such exoplanets,” Kate Isaak, ESA CHEOPS project scientist and co-author of the new study, said in a news release. “It will search for the transits of planets that have been discovered from the ground and, where possible, will more precisely measure the dimensions of the planets already known for the transit of their host stars.”

A new paper The description of the first formal investigation of the space telescope was published in Astronomy & Astrophysics.

WASP-189b is located 322 light-years away in the southern hemisphere constellation Libra. This superheated Jupiter is in a tight orbit around the type A star HD 133112, which lights up blue. The exoplanet, just 4.7 million miles (7.5 million km) from its host star, takes just 2.7 days to complete a full orbit. Given this cozy layout, about 5% of the way Earth to the Sun – WASP-189b is very hot, with new CHEOPS data refining previous estimates.

Illustration for the article titled A Distant Blue Star is home to one of the most extreme exoplanets known to science

Image: ESA

The temperature of WASP-189b is actually difficult to understand, because this gas giant is bright enough, causing conflicting data between itself and its host star. To get around this, Lendl and his colleagues have been waiting for occultations, where planets pass behind their host stars from our perspective (kind of like the opposite of the transit method). This allowed the scientists to correctly discern the exoplanet’s brightness, which in turn allowed them to measure its temperature.

“WASP-189b is one of the hottest known gas giants,” Lendl said. “With CHEOPS, we were able to determine the brightness of the planetary day side and find that the light emitted by it corresponds to a planet with a temperature of about 3,200 degrees Celsius. [5,800 degrees Fahrenheit]. “

It is intense; our Sun is only 2,000 degrees C (3,630 degrees F) hotter than this scorching exoplanet. And indeed, WASP-189b is actually hotter than some red dwarf stars, which cook at temperatures well below 3,000 degrees C (5,430 degrees F). The chances that there is life on this planet are practically nil, since iron also converts to gas at these extremes.

Few planets are known to be this hot. WASP-189b is also the brightest hot Jupiter known to scientists.

Researchers refined the mass of the exoplanet, discovering that it is almost exactly twice as heavy as Jupiter. They also updated the diameter of WASP-189b, finding it is 1.6 Width of Jupiter, or 139, 000 miles (224, 000 km), slightly larger than previous calculations.

Scientists also noted that the star, HD 133112, it is not perfectly round, it is actually a little flattened, protruding at the equator, where it is considerably cooler than in the polar regions. The star is fast spinning and the resulting centrifugal tidal forces are contributing to his odd shape, the authors note in the study.

Interestingly, WASP-189b is in an inclined orbit, which means it is out of line with the star’s equatorial plane. It actually is really misaligned, zooming in over the polar regions of the star. This is an important observation, as it means the exoplanet probably formed agorther out and then slowly migrated inland over time. This journey to the host star happened or due to the gravitational influence of other planets in the same system or the influence of another star, the researchers speculate.

With its complete WASP-189b observations, CHEOPS will now turn its attention to hundreds of other known exoplanets and their host stars, which it will do to further limit their mass, size and orbit. As this inaugural investigation makes clear, we can expect much more from this exciting new space telescope.


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