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.

arXiv commentPublished in Astronomy & Astrophysics. 11 pages, 11 figures, 4 tables

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• TESS Transit Timing of Hundreds of Hot Jupiters
• Physical properties, transmission and emission spectra of the WASP-19 planetary system from multi-colour photometry
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• The secondary eclipses of WASP-19b as seen by the ASTEP 400 telescope from Antarctica
• ExoClock Project III: 450 new exoplanet ephemerides from ground and space observations
• Ground-Based Transit Spectroscopy of the Hot-Jupiter WASP-19b in the Near-Infrared
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• High-precision photometry by telescope defocussing. VII. The ultra-short period planet WASP-103
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• Broad-band spectrophotometry of the hot Jupiter HAT-P-12b from the near-UV to the near-IR
• Ks band secondary eclipses of WASP-19b and WASP-43b with the Anglo-Australian Telescope
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• 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
• $TESS$ Phase Curve of the Hot Jupiter WASP-19b
• Examining the broadband emission spectrum of WASP-19b: A new z band eclipse detection
• Colour-magnitude diagrams of transiting Exoplanets - II. A larger sample from photometric distances
• ULTRACAM z'-band Detection of the Secondary Eclipse of WASP-12b
• High-precision multi-wavelength eclipse photometry of the ultra-hot gas giant exoplanet WASP-103 b
• Regaining the FORS: optical ground-based transmission spectroscopy of the exoplanet WASP-19b with VLT+FORS2
• TTVs analysis in Southern Stars: the case of WASP-28
• Broad-band spectrophotometry of HAT-P-32 b: Search for a scattering signature in the planetary spectrum
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• First Light of Engineered Diffusers at the Nordic Optical Telescope Reveal Time Variability in the Optical Eclipse Depth of WASP-12b
• Physical properties of the planetary systems WASP-45 and WASP-46 from simultaneous multi-band photometry
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• Ground-based follow-up observations of TRAPPIST-1 transits in the near-infrared
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• Super stellar abundances of alkali metals suggest significant migration for Hot Jupiters
• Measuring the orbit shrinkage rate of hot Jupiters due to tides
• Geometrical and Kinematic Parameters of the Jet of the Blazar S5 0716+71 in a Helical-Jet Model
• Evidence of apsidal motion and a possible co-moving companion star detected in the WASP-19 system
• Detection capability of ground-based meter-sized telescopes for shallow exoplanet transits
• Colour-colour and colour-magnitude diagrams for Hot Jupiters
• A dayside thermal inversion in the atmosphere of WASP-19b
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• 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
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