Researchers used the James Webb Space Telescope (JWST) to study the Hot Jupiter WASP-94A b. They found a daily cycle: clouds form each morning and clear by evening. This is one of the first detections of such a cycle on a Hot Jupiter.
The team observed the planet while it passed in front of its star. They took separate measurements of the planet's leading edge at the start of the transit (morning) and the trailing edge at the end (evening). At morning the air flows from the night side to the day side, and at evening the flow goes from day to night.
Observations show morning clouds made of magnesium silicate, a kind of rock, and clear evenings. The researchers suggest two ideas: strong winds could move clouds into the planet's interior, or the clouds could vaporize in more than 1,000 degrees on the day side.
Difficult words
- transit — when one object moves in front of another
- edge — the outer part or border of somethingleading edge, trailing edge
- vaporize — to change from liquid or solid into gas
- magnesium silicate — a mineral or rock made from magnesium and silicon
- cycle — a series of events that repeat regularly
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Discussion questions
- Which idea about the missing clouds do you think is more likely? Why?
- How is the planet's morning different from its evening, based on the text?
- Have you ever seen clouds change during one day on Earth? Describe briefly.
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