$TESS$ Phase Curve of the Hot Jupiter WASP-19b

TL;DR

This study presents the first atmospheric retrieval of WASP-19b's secondary eclipse spectrum from TESS data, revealing a hot, reflective dayside atmosphere with efficient heat redistribution.

Contribution

It provides the first atmospheric retrieval of WASP-19b using TESS phase curve data, combining optical and infrared observations for detailed atmospheric characterization.

Findings

WASP-19b's dayside temperature is approximately 2240 K.

The planet has a geometric albedo of about 0.16.

No significant nightside flux or offset detected.

Abstract

We analyze the phase curve of the short-period transiting hot Jupiter system WASP-19, which was observed by the Transiting Exoplanet Survey Satellite ($TESS$) in Sector 9. WASP-19 is one of only five transiting exoplanet systems with full-orbit phase curve measurements at both optical and infrared wavelengths. We measure a secondary eclipse depth of $470^{+130}_{-110}$ ppm and detect a strong atmospheric brightness modulation signal with a semi-amplitude of $319\pm51$ ppm. No significant offset is detected between the substellar point and the region of maximum brightness on the dayside. There is also no significant nightside flux detected, which is in agreement with the nightside effective blackbody temperature of $1090^{+190}_{-250}$ derived from the published $Spitzer$ phase curves for this planet. Placing the eclipse depth measured in the $TESS$ bandpass alongside the large body of previous values from the literature, we carry out the first atmospheric retrievals of WASP-19b's secondary eclipse spectrum using the SCARLET code. The retrieval analysis indicates that WASP-19b has a dayside atmosphere consistent with an isotherm at $T=2240\pm40$ K and a visible geometric albedo of $0.16\pm0.04$, indicating significant contribution from reflected starlight in the $TESS$ bandpass and moderately efficient day-night heat transport.