We have realized that planets and planetary systems are more diverse than we thought since the first planet was discovered. Exoplanets give us the chance to study planets in different ways. It's important to learn about their atmospheres.
TheJWST is the largest telescope in space. It was launched on Christmas day in 2021. We used the telescope for the first time to see the chemical make up of an exoplanet. The data released in preprint form suggests some surprising results.
Many exoplanets are too close to their parents for this telescope to distinguish them. As the planet passes in front of its star, we can use the trick to watch. During transit, the planet blocks a small portion of the starlight, and an even tinier portion of the starlight is passed through the atmosphere.
The fingerprints on the starlight are left by gases within the atmosphere that absorb some of the light. It is a telescope that can be used for atmosphere studies. Water vapor and carbon dioxide are some of the gases in the atmosphere that are odorless.
I am part of an international team of exoplanet scientists that is studying a Jupiter-sized planet called WASP 39b. This world is being cooked because it takes only a few days to travel around its star.
The most complete spectrum has yet to be recovered. Our work is the first chemical inventory of the atmosphere.
Most of the planet's atmosphere had to be a mixture of hydrogen and helium, the lightest gases in the universe. The Hubble telescope has been able to detect water vapor and other gasses there.
We have been able to produce a measurement of the amount of water Vapor. There are other gases like carbon dioxide, carbon monoxide, and sulfur dioxide, according to the data.
We can estimate the relative amounts of the elements that make up the gases by measuring how much they are present in the atmosphere. There is a disc of dust and gas around a young star, and we expect different amounts of elements to be available to a baby planet at different distances from the star.
WASP 39b appears to have a relatively low amount of carbon relative to oxygen, which suggests it probably formed at a greater distance from the star where it could have easily absorbed water ice from the disc. The idea that the giant planets in our Solar System did a bit of moving and shaking early on could be supported by the fact that this planet has migrated.
The key is sulfurous.
The amount of sulfur we detected is very high. Sulfur in a young planetary system should be more concentrated in bits of rock and rubble than it is in the atmosphere. This shows that WASP-39b may have had an unusual amount of collision with sulfur-laden chunks of rock. The sulfur would be released into the air.
Depending on the temperature of the planet, different chemicals react with each other at different rates. The total amount of each gas is usually stable as the reactions balance each other. We were able to predict the gases we would see in WASP 39b's atmosphere. They didn't come up with sulfur dioxide because they thought sulfur would be locked up in hydrogen sulfide.
A process called photochemistry was missing from the puzzle. The rates of certain chemical reactions are driven by the amount of light coming from the star rather than the temperature of the atmosphere. We didn't expect photochemistry to be as important as it has turned out to be because WASP-39b is so hot.
Water in the atmosphere is split into oxygen and hydrogen by light, according to the data. These products would react with hydrogen sulfide and replace it with oxygen to make sulfur dioxide.
What are the next steps for JWST?
The ozone layer on our own planet is formed through a photochemical process. The first year of operation will see the observation of the rocky worlds in the Trappist-1 system. All of the planets have temperatures similar to Earth's, and some have already been measured.
It's possible that some people have the right temperature to have liquid water on the surface. Understanding how photochemistry affects atmospheric composition is going to be important for interpreting the telescope observations. Since an apparent chemical imbalance in an atmosphere might hint at the presence of life, we need to be aware of other possibilities.
The WASP-39b inventory shows how powerful a tool is. We are at the beginning of a very exciting era in exoplanet science.
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