Lesson · beginner · 6 min
How Transit Spectra Reveal Atmospheres
Learn why a tiny dip in starlight during transit can expose molecules in an exoplanet's air.
Learning goal
Explain transit spectroscopy in plain language and know why infrared wavelengths help.
Steps
- A planet crosses its star (transit).
- A sliver of starlight filters through the atmosphere.
- Molecules absorb specific wavelengths.
- Comparing in-transit and out-of-transit spectra reveals atmospheric fingerprints.
Webb's infrared range is especially useful for water, carbon dioxide, and other key molecules.