Atmospheric Characterization of Five Hot Jupiters with the Wide Field Camera 3 on the Hubble Space Telescope
We probe the structure and composition of the atmospheres of five hot Jupiter exoplanets using the Hubble Space Telescope Wide Field Camera 3 (WFC3) instrument. We use the G141 grism (1.1-1.7 μm) to study TrES-2b, TrES-4b, and CoRoT-1b in transit; TrES-3b in secondary eclipse; and WASP-4b in both. This wavelength region includes a predicted absorption feature from water at 1.4 μm, which we expect to be nondegenerate with the other molecules that are likely to be abundant for hydrocarbon-poor (e.g., solar composition) hot Jupiter atmospheres. We divide our wavelength regions into 10 bins. For each bin we produce a spectrophotometric light curve spanning the time of transit or eclipse. We correct these light curves for instrumental systematics without reference to an instrument model. For our transmission spectra, our mean 1σ precision per bin corresponds to variations of 2.1, 2.8, and 3.0 atmospheric scale heights for TrES-2b, TrES-4b, and CoRoT-1b, respectively. We find featureless spectra for these three planets. We are unable to extract a robust transmission spectrum for WASP-4b. For our dayside emission spectra, our mean 1σ precision per bin corresponds to a planet-to-star flux ratio of 1.5 × 10^(–4) and 2.1 × 10^(–4) for WASP-4b and TrES-3b, respectively. We combine these estimates with previous broadband measurements and conclude that for both planets isothermal atmospheres are disfavored. We find no signs of features due to water. We confirm that WFC3 is suitable for studies of transiting exoplanets, but in staring mode multivisit campaigns are necessary to place strong constraints on water abundance.
Additional Information© 2014 American Astronomical Society. Received 2013 June 17; accepted 2014 March 4; published 2014 April 4. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute (STScI). These observations are associated with program HST-GO-12181. Support for this program was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship under grant No. DGE-1144152. This work was also performed in part under contract with the California Institute of Technology (Caltech) funded by NASA through the Sagan Fellowship Program grant awarded to J.-M.D. N.M. acknowledges support from Yale University through the YCAA postdoctoral prize fellowship. This research has made use of the Exoplanet Orbit Database and the Exoplanet Data Explorer at exoplanets.org; the SIMBAD database, operated at CDS, Strasbourg, France; NASA's Astrophysics Data System Bibliographic Services; and SAOImage DS9, developed by Smithsonian Astrophysical Observatory. The authors are grateful to Z. Berta-Thompson and J. Carter for many fruitful discussions, to the STScI HST help team for their assistance, and to an anonymous referee whose comments strengthened the paper. Facility: HST (WFC3)
Published - 0004-637X_785_2_148.pdf
Submitted - 1403.1266v1.pdf