ACCESS: A Visual to Near-infrared Spectrum of the Hot Jupiter WASP-43b with Evidence of H O, but no evidence of Na or K. (arXiv:1911.03358v1 [astro-ph.EP])

4 years ago

ACCESS: A Visual to Near-infrared Spectrum of the Hot Jupiter WASP-43b with Evidence of HO, but no evidence of Na or K. (arXiv:1911.03358v1 [astro-ph.EP])

Ian C. Weaver, Mercedes López-Morales, Néstor Espinoza, Benjamin V. Rackham, David J. Osip, Dániel Apai, Andrés Jordán, Alex Bixel, Nikole K. Lewis, Munazza K. Alam, James Kirk, Chima McGruder, Florian Rodler, Jennifer Fienco

We present a new ground-based visual transmission spectrum of the hot Jupiter WASP-43b, obtained as part of the ACCESS Survey. The spectrum was derived from four transits observed between 2015 and 2018, with combined wavelength coverage between 5,300 \r{A}-9,000 \r{A} and an average photometric precision of 708 ppm in 230 \r{A} bins. We perform an atmospheric retrieval of our transmission spectrum combined with literature HST/WFC3 observations to search for the presence of clouds/hazes as well as Na, K, H, and planetary absorption and stellar spot contamination over a combined spectral range of 5,318 \r{A}-16,420 \r{A}. We do not detect a statistically significant presence of Na I or K I alkali lines, or H in the atmosphere of WASP-43b. We find that the observed transmission spectrum can be best explained by a combination of heterogeneities on the photosphere of the host star and a clear planetary atmosphere with . This model yields a log-evidence of higher than a flat (featureless) spectrum. In particular, the observations marginally favor the presence of large, low-contrast spots over the four ACCESS transit epochs with an average covering fraction and temperature contrast . Within the planet's atmosphere, we recover a log volume mixing ratio of , which is consistent with previous abundance determinations for this planet.

Publisher URL: http://arxiv.org/abs/1911.03358

DOI: arXiv:1911.03358v1