Ground-based detection of thermal emission from the exoplanet WASP-19b

TL;DR

This study reports the detection of thermal emission from exoplanet WASP-19b using ground-based infrared observations, revealing a high brightness temperature and suggesting poor heat redistribution on the planet.

Contribution

First ground-based measurement of thermal emission from WASP-19b's dayside at ~2 micrometers, providing insights into its atmospheric properties.

Findings

Brightness temperature of 2540±180 K

Indication of poor heat redistribution

Orbit consistent with circular orbit

Abstract

We present an occultation of the newly discovered hot Jupiter system WASP-19, observed with the HAWK-I instrument on the VLT, in order to measure thermal emission from the planet's dayside at ~2 um. The light curve was analysed using a Markov-Chain Monte-Carlo method to find the eclipse depth and the central transit time. The transit depth was found to be 0.366+-0.072 %, corresponding to a brightness temperature of 2540+-180 K. This is significantly higher than the calculated (zero-albedo) equilibrium temperature, and indicates that the planet shows poor redistribution of heat to the night side, consistent with models of highly irradiated planets. Further observations are needed to confirm the existence of a temperature inversion, and possibly molecular emission lines. The central eclipse time was found to be consistent with a circular orbit.