Linked from
The 16 pages that link to Transmission spectroscopy, each with the reason it gives.
ExoplanetRelated: It can identify atmospheric molecules by their wavelength-dependent absorption.
TRAPPIST-1Related: It tests whether the planets have detectable atmospheric gases or clouds.
Planetary transitBroader topic: Wavelength-dependent dimming can reveal atmospheric gases.
HD 209458 bRelated: Atmospheric absorption changes the transit spectrum of this planet.
Earth analogRelated: Atmospheric spectra can test whether a small planet has gases unlike Earth's.
K2-18bRelated: It has been used to identify and constrain gases in K2-18b’s atmosphere.