Joanna K. Barstow

VLT FORS2 comparative transmission spectroscopy: Detection of Na in the atmosphere of WASP-39b from the ground

We present transmission spectroscopy of the warm Saturn-mass exoplanet WASP-39b made with the Very Large Telescope FOcal Reducer and Spectrograph (FORS2) across the wavelength range 411–810 nm. The transit depth is measured with a typical precision of 240 parts per million (ppm) in wavelength bins of 10 nm on a V = 12.1 mag star. We detect the sodium absorption feature (3.2σ) and find evidence of potassium. The ground-based transmission spectrum is consistent with Hubble Space Telescope (HST) optical spectroscopy, supporting the interpretation that WASP-39b has a largely clear atmosphere. Our results demonstrate the great potential of the recently upgraded FORS2 spectrograph for optical transmission spectroscopy, with which we obtained HST-quality light curves from the ground.

Variability in the atmosphere of the hot giant planet HAT-P-7 b

The detection of temporal variations in the peak of the phase curve of the hot giant exoplanet HAT-P-7 b is explained by changes in wind speed and cloud coverage in its atmosphere. Such ‘weather’ has never before been observed on a giant exoplanet.

VLT/FORS2 comparative transmission spectroscopy II: confirmation of a cloud-deck and Rayleigh scattering in WASP-31b, but no potassium?

We present transmission spectroscopy of the hot-Jupiter WASP-31b using FORS2 on the VLT during two primary transits. The observations cover a wavelength range of

The Complete Transmission Spectrum of WASP-39b with a Precise Water Constraint

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HST PanCET Program: A Cloudy Atmosphere for the Promising JWST Target WASP-101b

400-840nm. The light curves are corrupted by significant systematics, but these were to first order invariant with wavelength and could be removed using a common-mode correction derived from the white light curves. We reach a precision in the transit depth of

A Framework for Prioritizing the TESS Planetary Candidates Most Amenable to Atmospheric Characterization

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The Very Low Albedo of WASP-12b from Spectral Eclipse Observations with Hubble

140 ppm in 15 nm bins, although the precision varies significantly over the wavelength range. Our FORS2 observations confirm the cloud-deck previously inferred using HST/STIS. We also re-analyse the HST/STIS data using a Gaussian process model, finding excellent agreement with earlier measurements. We reproduce the Rayleigh scattering signature at short wavelengths (

Exoplanets with JWST: degeneracy, systematics and how to avoid them

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An absolute sodium abundance for a cloud-free ‘hot Saturn’ exoplanet

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Hubble PanCET: an isothermal day-side atmosphere for the bloated gas-giant HAT-P-32Ab

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