Planets that transit their host stars – as seen from Earth – occult part of their host star’s disk, providing a unique opportunity to study their atmospheres. The larger the planet, the greater the dimming of the starlight due to the occultation. Thus, a simple but precise measurement of the dimming of the star can reveal the size of the planet relative to its host star. For an extended atmosphere the size of the planet (and its atmosphere) will also depend on the wavelength of observations: at wavelength where an absorber is present the planet will be larger. Therefore, measuring the relative size of the planet as a function of wavelength can reveal the presence of atmospheric absorbers.
Our ACCESS Survey is utilizing large ground-based telescopes — the 6.5m Magellan telescopes in Chile and the 6.5m MMT in Arizona — to compile the largest library of transmission spectra of transiting planets.
The ACCESS Survey Team:
Daniel Apai, Co-PI (Univ. Arizona),
Nestor Espinoza (Catholic University, Chile)
Jonathan Fortney (UCSD)
Jonathan Fraine (U Maryland)
Andres Jordan (Catholic University, Chile), Co-PI
Nikole Lewis (STScI)
Mercedes Lopez-Morales (Harvard-Smithsonian CfA), Co-PI
David Osip (Carnegie Observatories)
Benjamin Rackham (Univ. Arizona)
Florian Rodler (MPIA)