This spacecraft will detect if exoplanet skies are cloudy, hazy, or c – Astronomy Magazine

Thousands of SkiesSo far, astronomers have discovered thousands of exoplanets that pass in front of their stars from our point of view. With the right tools, astronomers can study light from the host stars that pass through the planets atmospheres. This can reveal information like the chemical makeup and temperatures of these atmospheres as well as what chemical reactions are taking place there.

The James Webb Space Telescope, currently scheduled to launch in 2021, will be able to study exoplanet atmospheres. But since JWST will split its time between multiple projects, it will only focus on studying the atmospheres of a few exoplanets. ARIEL, however, will observe the skies of about 1,000 exoplanets, from rocky planets to Jupiter-like gas giants.

Im really looking forward to the ability to place individual planets within a statistical context, says Mark Swain, an astrophysicist at NASAs Jet Propulsion Laboratory who is heading production of the CASE instrument. That is something which you need a large survey of exoplanets to do.

Understanding whether an exoplanet has clouds or hazes will help astronomers better interpret other information about the planets atmosphere, like chemical makeup and temperature, and figure out what physical and chemical processes are happening.

Also, understanding chemical compositions of exoplanet atmospheres might help decide which of two leading theories for how planets form is most likely correct. One theory suggests that planets will tend to have similar fractions of heavy elements as their host stars, while another implies that the heavy element fractions could be quite different.

Finally, studying the atmospheres of 1,000 planets should help astronomers find out whats typical and pick out interesting cases to delve into.

When we see a single planet, a big question is, Is this kind of like the others, or did something special happen here? Swain says. And thats a fundamental capability that ARIEL is going to give us.

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This spacecraft will detect if exoplanet skies are cloudy, hazy, or c - Astronomy Magazine