A New Optical Transmission Spectrum of WASP-43b from ACCESS

We present a new ground-based optical transmission spectrum of the hot Jupiter WASP-43b (Mp = 2.03 MJ, Rp = 1.04 RJ) obtained with the Inamori-Magellan Areal Camera and Spectrograph (IMACS) on the Baade Telescope at Las Campanas Observatory.  Using multi-object differential spectrophotometry, we produce a high precision spectrum of this planet between 400 and 900 nm, combining three different transit epochs. A variety of binsizes ranging from 10-75nm is also used to compare with recent measurements of the optical spectrum of this planet, which suggest the presence of Na I absorption. In this analysis, we search for signals of Na I and K I, as well as for the presence of hazes/clouds. These observations were made as part of ACCESS (Arizona-CfA-Católica-Carnegie Exoplanet Spectroscopy Survey),  which aims at providing the largest uniform sample of visible transmission spectra of giant exoplanets. We expect ACCESS will also play a key role in providing optical exoplanet transmission spectra in the JWST era.

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