ACCESS: A Visual to Near-infrared Spectrum of the Hot Jupiter WASP-43b with Evidence of H2O, but No Evidence of Na or K

Weaver, IC; Lopez-Morales, M; Espinoza, N; Rackham, BV; Osip, DJ; Apai, D; Jordan, A; Bixel, A; Lewis, NK; Alam, MK; Kirk, J; McGruder, C; Rodler, F; Fienco, J

Abstract

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 5300 and 9000 A and an average photometric precision of 708 ppm in 230 A bins. We perform an atmospheric retrieval of our transmission spectrum combined with literature Hubble Space Telescope/WFC3 observations to search for the presence of clouds/hazes as well as Na, K, H alpha, and H2O planetary absorption and stellar spot contamination over a combined spectral range of 5318-16420 A. We do not detect a statistically significant presence of Na i or K i alkali lines, or H alpha 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 H2O. This model yields a log evidence of 8.26 0.42 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 T = 132 K 132 K. Within the planet's atmosphere, we recover a log H2O volume mixing ratio of -2.78(-1.47)(+1.38), which is consistent with previous H2O abundance determinations for this planet.

Más información

Título según WOS: ACCESS: A Visual to Near-infrared Spectrum of the Hot Jupiter WASP-43b with Evidence of H2O, but No Evidence of Na or K
Título de la Revista: ASTRONOMICAL JOURNAL
Volumen: 159
Número: 1
Editorial: IOP PUBLISHING LTD
Fecha de publicación: 2020
Idioma: English
DOI:

10.3847/1538-3881/ab55da

Notas: ISI