The Flat Transmission Spectrum of the Super-earth Gj1214b From Wide Field Camera 3 on the Hubble Space Telescope
Berta, Zachory K.
Miller-Ricci Kempton, Eliza
McCullough, Peter R.
Burke, Christopher J.
Fortney, Jonathan J.
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CitationBerta, Zachory K., David Charbonneau, Jean-Michel Désert, Eliza Miller-Ricci Kempton, Peter R. McCullough, Christopher J. Burke, Jonathan J. Fortney, Jonathan Irwin, Philip Nutzman, and Derek Homeier. 2012. “THE FLAT TRANSMISSION SPECTRUM OF THE SUPER-EARTH GJ1214b FROM WIDE FIELD CAMERA 3 ON THEHUBBLE SPACE TELESCOPE.” The Astrophysical Journal 747 (1): 35. https://doi.org/10.1088/0004-637x/747/1/35.
AbstractCapitalizing on the observational advantage offered by its tiny M dwarf host, we present Hubble Space Telescope/Wide Field Camera 3 (WFC3) grism measurements of the transmission spectrum of the super-Earth exoplanet GJ1214b. These are the first published WFC3 observations of a transiting exoplanet atmosphere. After correcting for a ramp-like instrumental systematic, we achieve nearly photon-limited precision in these observations, finding the transmission spectrum of GJ1214b to be flat between 1.1 and 1.7 mu m. Inconsistent with a cloud-free solar composition atmosphere at 8.2 sigma, the measured achromatic transit depth most likely implies a large mean molecular weight for GJ1214b's outer envelope. A dense atmosphere rules out bulk compositions for GJ1214b that explain its large radius by the presence of a very low density gas layer surrounding the planet. High-altitude clouds can alternatively explain the flat transmission spectrum, but they would need to be optically thick up to 10 mbar or consist of particles with a range of sizes approaching 1 mu m in diameter.
Citable link to this pagehttp://nrs.harvard.edu/urn-3:HUL.InstRepos:41397416
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