Planet WASP-178b was discovered in 2019 based on data previously collected by the WASP-South telescope. She is on
WASP-178b always faces its star aloneside, which causes a significant difference in temperatures in the solar and shadow hemispheres of the planet. In a study published in the journal Nature, astronomers show that WASP-178b's dayside atmosphere is cloudless but contains large amounts of silicon monoxide (SiO). The difference in atmospheric temperature creates powerful air currents that move towards the shadow part of the planet at a speed of over 3 thousand km/h.
On the night side in the upper atmosphereplanet SiO cools, condenses and falls on the surface of the planet as a stone rain. At the same time, as the researchers note, even on the shadow side, the surface of WASP-178b is warm enough to evaporate rocks, return silicon monoxide to the atmosphere and start a kind of cycle.
The second study on hotJupiter, was published in the Astrophysical Journal Letters. Using Hubble data, astronomers studied the hot Jupiter KELT-20b, located 400 light-years from Earth and 0.054 AU. from your star. The surface temperature of this planet is almost 2,000°C.
At the top of the atmosphere KELT-20b scientistsfound a hot layer similar to the Earth's stratosphere. It is formed, as researchers believe, under the influence of ultraviolet radiation from a star. On Earth, the ozone layer absorbs UV radiation, which leads to a heating of the atmosphere at an altitude of 10 to 50 km above sea level. On KELT-20b, a similar function is performed by metals, which create a very powerful inversion layer: the atmosphere becomes colder as you move up from the surface, but at high altitude there is a sharp rise in temperature.
This discovery was made possible by the discoveryHubble of water vapor by observing KELT-20b in the near infrared range, as well as due to the discovery by the Spitzer telescope of the existence of carbon monoxide on the planet. The scientists note that the "traces" of these gases in the infrared create a unique image, uncharacteristic of other hot Jupiters that orbit cooler stars.
“The emission spectrum of KELT-20b is very different fromspectra of other hot Jupiters,” says Guangwei Fu, co-author of the study. “This is compelling evidence that planets do not live in isolation, but are influenced by their host star.”
Although hot Jupiters are uninhabitable, astronomers say this kind of research helps to better understand the atmosphere of potentially habitable terrestrial planets.
If we can't understand what's going onsuper-hot Jupiters, for which we have reliable observational data, we will not have a chance to find out what is happening on terrestrial exoplanets, whose emission spectrum is much weaker. This is a test of our methods and helps us gain a general understanding of cloud formation processes and atmospheric structure.
Joshua Lotringer, an astronomer at Utah Valley University and co-author of both studies
Hot Jupiters are a class of exoplanets, masswhich is comparable to the mass of Jupiter. However, unlike the gas giant of the solar system, such planets are very close to their star, at a distance of about 0.05 AU. This is almost 10 times less than the distance between the Sun and Mercury. Due to its proximity to the star, the planet's atmosphere can heat up to temperatures of 1,500°C or even higher. This is enough to melt, and sometimes even turn into steam, most metals.
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