Exploring the stellar surface phenomena of WASP-52 and HAT-P-30 with ESPRESSO

Abstract

We analyse spectroscopic and photometric transits of the hot Jupiters WASP-52b and HAT-P30b obtained with ESPRESSO, Eulercam and NGTS for both targets, and additional TESS data for HAT-P-30. Our goal is to update the system parameters and refine our knowledge of the host star surfaces. For WASP-52, the companion planet has occulted starspots in the past, and as such our aim was to use the reloaded Rossiter-McLaughlin technique to directly probe its starspot properties. Unfortunately, we find no evidence for starspot occultations in the datasets herein. Additionally, we searched for stellar surface differential rotation (DR) and any centre-to-limb variation (CLV) due to convection, but return a null detection of both. This is unsurprising for WASP-52, given its relatively cool temperature, high magnetic activity (which leads to lower CLV), and projected obliquity near 0 degrees (meaning the transit chord is less likely to cross several stellar latitudes). For HAT-P-30, this result was more surprising given its hotter effective temperature, lower magnetic field, and high projected obliquity (near 70 degrees). To explore the reasons behind the null DR and CLV detection for HAT-P-30, we simulated a variety of scenarios. We find that either the CLV present on HAT-P-30 is below the solar level or the presence of DR prevents a CLV detection given the precision of the data herein. A careful treatment of both DR and CLV is required, especially for systems with high impact factors, due to potential degeneracies between the two. Future observations and/or a sophisticated treatment of the red noise present in the data (likely due to granulation) is required to refine the DR and CLV for these particular systems; such observations would also present another opportunity to try to examine starspots on WASP-52.

11 pages main text, 8 figures; accepted for publication in A&A

References in corpus (22)

• The Transiting Exoplanet Survey Satellite
• Water Vapor in the Spectrum of the Extrasolar Planet HD 189733b: 1. the Transit
• Limb darkening and exoplanets: testing stellar model atmospheres and identifying biases in transit parameters
• SOAP 2.0: A tool to estimate the photometric and radial velocity variations induced by stellar spots and plages
• Orbital misalignment of the Neptune-mass exoplanet GJ 436b with the spin of its cool star
• WASP-42 b and WASP-49 b: two new transiting sub-Jupiters
• Impact of occultations of stellar active regions on transmission spectra: Can occultation of a plage mimic the signature of a blue sky?
• WASP-80b has a dayside within the T-dwarf range
• Filtering solar-like oscillations for exoplanet detection in radial velocity observations
• Search for water vapor in the high-resolution transmission spectrum of HD189733b in the visible
• Transmission spectroscopy of the inflated exoplanet WASP-52b, and evidence for a bright region on the stellar surface
• TOI-222: a single-transit TESS candidate revealed to be a 34-day eclipsing binary with CORALIE, EulerCam and NGTS
• WASP-52b. The effect of starspot correction on atmospheric retrievals
• Refined architecture of the WASP-8 system: a cautionary tale for traditional Rossiter-McLaughlin analysis
• The polar orbit of the warm Neptune GJ436b seen with VLT/ESPRESSO
• The Impact of Stellar Surface Magnetoconvection and Oscillations on the Detection of Temperate, Earth-Mass Planets Around Sun-Like Stars
• Detecting transit signatures of exoplanetary rings using SOAP3.0
• Spatially resolved spectroscopy across stellar surfaces. II. High-resolution spectra across HD209458 (G0V)
• Can stellar activity make a planet seem misaligned?
• Spatially resolved spectroscopy across stellar surfaces. V. Observational prospects: Toward Earth-like exoplanet detection
• The Hot Neptune WASP-166~b with ESPRESSO I: Refining the Planetary Architecture and Stellar Variability
• Optimal parameter space for detecting stellar differential rotation and centre-to-limb convective variations

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• A Population Analysis of 20 Exoplanets Observed from the Optical to the Near-infrared Wavelengths with HST: Evidence for Widespread Stellar Contamination
• Exploring the surface of HD 189733 via Doppler shadow analysis of planetary transits