Detection of Na I & A Cloudy Atmosphere at the Limb of the Inflated Hot Jupiter WASP-52b

Thursday 5 July, 09:20

We present a precise optical to near-infrared transmission spectrum of the inflated hot Jupiter WASP-52b using three transit observations from HST/STIS, combined with one transit from Spitzer/IRAC at 3.6 microns. Since WASP-52 is a moderately active star, we correct the transit light curves for the effect of stellar activity using ground-based activity monitoring data from the All-Sky Automated Survey for Supernovae (ASSA-SN) and Tennessee State University's Celestron Automatic Imaging Telescope (AIT). We bin the data in 23 spectrophotometric light curves from 0.29 to 3.6 microns and measure the transit depths to a median precision of 68 ppm. We fit the transmission spectrum to a grid of forward atmospheric models, and find that our results are consistent with a flat (cloudy) spectrum and a 2.3-sigma detection of Na I. This result is part of the HST Panchromatic Comparative Exoplanetary Treasury (PanCET) Program (GO 14767).

Submitted by