David Charbonneau
= David Charbonneau
{c}
<David Charbonneau> detected atmospheric absorption in a transiting <exoplanet> by comparing the transit depth in different <wavelength> bands. His team's observations of <HD 209458 b> found extra dimming near the <sodium> resonance lines relative to adjacent spectral bands.
During an <exoplanet transit>, a small fraction of the stellar <light> passes through the planetary limb. Absorbing atmospheric <gas> therefore changes the apparent blocking area with <wavelength>. The observed feature was weaker than a particular cloud-free model predicted, illustrating why detecting an atmospheric species and uniquely determining the atmospheric structure are different inference problems.<Detection of an Extrasolar Planet Atmosphere by David Charbonneau and others>[Abstract: four transits, differential sodium absorption and possible explanations of reduced amplitude]{ref}
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{title=Portrait of <David Charbonneau>}
{description=NASA/Spitzer Space Telescope portrait published in 2005; public-domain image record on Wikimedia Commons.}
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