A photometric study of the hot exoplanet WASP-19b

Abstract

Context: When the planet transits its host star, it is possible to measure the planetary radius and (with radial velocity data) the planet mass. For the study of planetary atmospheres, it is essential to obtain transit and occultation measurements at multiple wavelengths. Aims: We aim to characterize the transiting hot Jupiter WASP-19b by deriving accurate and precise planetary parameters from a dedicated observing campaign of transits and occultations. Methods: We have obtained a total of 14 transit lightcurves in the r'-Gunn, IC, z'-Gunn and I+z' filters and 10 occultation lightcurves in z'-Gunn using EulerCam on the Euler-Swiss telescope and TRAPPIST. We have also obtained one lightcurve through the narrow-band NB1190 filter of HAWK-I on the VLT measuring an occultation at 1.19 micron. We have performed a global MCMC analysis of all new data together with some archive data in order to refine the planetary parameters and measure the occultation depths in z'-band and at 1.19 micron. Results: We measure a planetary radius of R_p = 1.376 (+/-0.046) R_j, a planetary mass of M_p = 1.165 (+/-0.068) M_j, and find a very low eccentricity of e = 0.0077 (+/-0.0068), compatible with a circular orbit. We have detected the z'-band occultation at 3 sigma significance and measure it to be dF_z'= 352 (+/-116) ppm, more than a factor of 2 smaller than previously published. The occultation at 1.19 micron is only marginally constrained at dF_1190 = 1711 (+/-745) ppm. Conclusions: We have shown that the detection of occultations in the visible is within reach even for 1m class telescopes if a considerable number of individual events are observed. Our results suggest an oxygen-dominated atmosphere of WASP-19b, making the planet an interesting test case for oxygen-rich planets without temperature inversion.

Published in Astronomy & Astrophysics. 11 pages, 11 figures, 4 tables

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Cited by in corpus (35)

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• ExoClock project II: A large-scale integrated study with 180 updated exoplanet ephemerides
• The EBLM Project V. Physical properties of ten fully convective, very-low-mass stars
• A Spectral Survey of WASP-19b with ESPRESSO
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• Low albedos of hot to ultra-hot Jupiters in the optical to near-infrared transition regime
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• Colour-magnitude diagrams of transiting Exoplanets - II. A larger sample from photometric distances
• High-precision multi-wavelength eclipse photometry of the ultra-hot gas giant exoplanet WASP-103 b
• TTVs analysis in Southern Stars: the case of WASP-28
• Regaining the FORS: optical ground-based transmission spectroscopy of the exoplanet WASP-19b with VLT+FORS2
• Broad-band spectrophotometry of HAT-P-32 b: Search for a scattering signature in the planetary spectrum
• Transiting Exoplanet Monitoring Project (TEMP). II. Refined System Parameters and Transit Timing Analysis of HAT-P-33b
• Discarding orbital decay in WASP-19b after one decade of transit observations
• Transmission spectroscopy of the ultra-hot Jupiter MASCARA-4 b: Disentangling the hydrostatic and exospheric regimes of ultra-hot Jupiters
• Storms or Systematics? The changing secondary eclipse depth of WASP-12b
• Moreton and EUV Waves Associated with an X1.0 Flare and CME Ejection
• A New Yield Simulator for Transiting Planets and False Positives: Application to the Next Generation Transit Survey
• Ground-based follow-up observations of TRAPPIST-1 transits in the near-infrared
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• Ground-based photometry of the 21-day Neptune HD106315c
• Evidence of apsidal motion and a possible co-moving companion star detected in the WASP-19 system
• Colour-colour and colour-magnitude diagrams for Hot Jupiters
• Detection capability of ground-based meter-sized telescopes for shallow exoplanet transits
• A dayside thermal inversion in the atmosphere of WASP-19b
• Planet-star interactions with precise transit timing. IV. Probing the regime of dynamical tides for GK host stars
• TESS Unveils the Full Phase Curve of WASP-19b
• A Global Perspective with Updated Constraints on the Ultra-hot Jupiter WASP-19b: Atmospheric Properties and Stellar Activity
• A new method to correct for host star variability in multi-epoch observations of exoplanet transmission spectra