Ks band secondary eclipses of WASP-19b and WASP-43b with the Anglo-Australian Telescope

TL;DR

This study reports Ks band secondary eclipse measurements of WASP-19b and WASP-43b using the AAT, compares them with atmospheric models, and assesses the detection capabilities of the observational setup.

Contribution

It provides new Ks band eclipse data for two hot Jupiters and evaluates the detection thresholds of the AAT+IRIS2 system for exoplanet atmospheres.

Findings

Significant secondary eclipses detected for both planets.

Optimal detection for targets brighter than Kmag 9.

Eclipses as shallow as 0.05% detectable at >5 sigma.

Abstract

We report new Ks band secondary eclipse observations for the hot-Jupiters WASP-19b and WASP-43b. Using the IRIS2 infrared camera on the Anglo-Australian Telescope (AAT), we measured significant secondary eclipses for both planets, with depths of 0.287 -0.020/+0.020% and 0.181 -0.027/+0.027% for WASP-19b and WASP-43b respectively. We compare the observations to atmosphere models from the VSTAR line-by-line radiative transfer code, and examine the effect of C/O abundance, top layer haze, and metallicities on the observed spectra. We performed a series of signal injection and recovery exercises on the observed light curves to explore the detection thresholds of the AAT+IRIS2 facility. We find that the optimal photometric precision is achieved for targets brighter than Kmag = 9, for which eclipses as shallow as 0.05% are detectable at >5 sigma significance.