ACCESS: A Visual to Near-infrared Spectrum of the Hot Jupiter WASP-43b with Evidence of ${\mathrm{H}}_2\mathrm{O}$, but no evidence of Na or K

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 5,300 Å-9,000 Å and an average photometric precision of 708 ppm in 230 Å 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$\alpha$, and ${\mathrm{H}}_2\mathrm{O}$ planetary absorption and stellar spot contamination over a combined spectral range of 5,318 Å-16,420 Å. 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 ${\mathrm{H}}_2\mathrm{O}$. This model yields a log-evidence of $8.26\pm 0.42$ 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 $f_{\text{het}}=0.27_{-0.16}^{+0.42}$ and temperature contrast $\Delta T=132\text{ K}\pm 132\text{ K}$. Within the planet's atmosphere, we recover a log ${\mathrm{H}}_2\mathrm{O}$ volume mixing ratio of $-2.78_{-1.47}^{+1.38}$, which is consistent with previous ${\mathrm{H}}_2\mathrm{O}$ abundance determinations for this planet.

27 pages, 18 figures, 7 tables. Accepted for publication in AJ. Updated affiliations

References in corpus (24)

• The NumPy array: a structure for efficient numerical computation
• Bayes in the sky: Bayesian inference and model selection in cosmology
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0
• Detection of atmospheric haze on an extrasolar planet: The 0.55 - 1.05 micron transmission spectrum of HD189733b with the Hubble Space Telescope
• The Gemini Planet Imager Exoplanet Survey: Giant Planet and Brown Dwarf Demographics From 10-100 AU
• A Precise Water Abundance Measurement for the Hot Jupiter WASP-43b
• The imprint of exoplanet formation history on observable present-day spectra of hot Jupiters
• Thermal structure of an exoplanet atmosphere from phase-resolved emission spectroscopy
• Water Vapor in the Spectrum of the Extrasolar Planet HD 189733b: 1. the Transit
• Water Vapour Absorption in the Clear Atmosphere of an exo-Neptune
• The Atmospheric Signatures of Super-Earths: How to Distinguish Between Hydrogen-Rich and Hydrogen-Poor Atmospheres
• Transmission spectral properties of clouds for hot Jupiter exoplanets
• The Atmospheric Circulation of the Hot Jupiter WASP-43b: Comparing Three-Dimensional Models to Spectrophotometric Data
• ACCESS I: An Optical Transmission Spectrum of GJ 1214b Reveals a Heterogeneous Stellar Photosphere
• The Transit Light Source Effect II: The Impact of Stellar Heterogeneity on Transmission Spectra of Planets Orbiting Broadly Sun-like Stars
• Trends in Atmospheric Properties of Neptune-Size Exoplanets
• Impact of occultations of stellar active regions on transmission spectra: Can occultation of a plage mimic the signature of a blue sky?
• spotrod: a semi-analytic model for transits of spotted stars
• Potassium detection in the clear atmosphere of a hot-Jupiter: FORS2 transmission spectroscopy of WASP-17b
• HST PanCET program: A Cloudy Atmosphere for the promising JWST target WASP-101b
• LRG-BEASTS III: Ground-based transmission spectrum of the gas giant orbiting the cool dwarf WASP-80
• An analytical formalism accounting for clouds and other "surfaces" for exoplanet transmission spectroscopy
• SALT observations of the Chromospheric Activity of Transiting Planet Hosts: Mass Loss and Star Planet Interactions
• ACCESS: Ground-based Optical Transmission Spectroscopy of the Hot Jupiter WASP-4b

Cited by in corpus (24)

• The ExoMolOP Database: Cross-sections and k-tables for Molecules of Interest in High-Temperature Exoplanet Atmospheres
• ExoClock Project III: 450 new exoplanet ephemerides from ground and space observations
• ACCESS & LRG-BEASTS: a precise new optical transmission spectrum of the ultrahot Jupiter WASP-103b
• On Atmospheric Retrievals of Exoplanets with Inhomogeneous Terminators
• Exoplanet atmosphere retrievals in 3D using phase curve data with ARCiS: application to WASP-43b
• Aluminium oxide in the atmosphere of hot Jupiter WASP-43b
• The GTC exoplanet transit spectroscopy survey XI. Possible detection of Rayleigh scattering in the atmosphere of the Saturn-mass planet WASP-69b
• The HST PanCET Program: An Optical to Infrared Transmission Spectrum of HAT-P-32Ab
• LRG-BEASTS: sodium absorption and Rayleigh scattering in the atmosphere of WASP-94A b using NTT/EFOSC2
• JWST-TST DREAMS: NIRSpec/PRISM Transmission Spectroscopy of the Habitable Zone Planet TRAPPIST-1 e
• The phase curve and the geometric albedo of WASP-43b measured with CHEOPS, TESS and HST WFC3/UVIS
• ACCESS: Confirmation of a Clear Atmosphere for WASP-96b and a Comparison of Light Curve Detrending Techniques
• An enhanced slope in the transmission spectrum of the hot Jupiter WASP-104b
• A new method to measure the spectra of transiting exoplanet atmospheres using multi-object spectroscopy
• ACCESS: Confirmation of no potassium in the atmosphere of WASP-31b
• Investigation of an orbital decay and global modeling of the planet WASP-43 b
• Transmission spectroscopy with VLT FORS2: a featureless spectrum for the low-density transiting exoplanet WASP-88b
• ACCESS: An optical transmission spectrum of the high-gravity, hot Jupiter HAT-P-23b
• Characterizing WASP-43b's interior structure: unveiling tidal decay and apsidal motion
• LRG-BEASTS: Evidence for clouds in the transmission spectrum of HATS-46 b
• ACCESS: Tentative detection of H${}_2$O in the ground-based optical transmission spectrum of the low-density hot Saturn HATS-5b
• A Measurement of the Water Abundance in the Atmosphere of the Hot Jupiter WASP-43b with High-resolution Cross-correlation Spectroscopy
• HAT-P-68b: A Transiting Hot Jupiter Around a K5 Dwarf Star
• Low-resolution Transit Spectroscopy of Three Hot Jupiters Using the 2m Himalayan Chandra Telescope