Thermal Emission from Transiting Very-Hot Jupiters: Prospects for Ground-based Detection at Optical Wavelengths

TL;DR

This paper assesses the potential for ground-based optical detection of thermal emission from very hot Jupiters during secondary eclipses, highlighting promising candidates and the implications of potential non-detections.

Contribution

It evaluates the feasibility of detecting optical thermal emission from VHJs with current telescopes and identifies optimal targets and wavelengths for such observations.

Findings

OGLE-TR-56b and OGLE-TR-132b are prime candidates for detection.

Detection prospects are highest around the z'-band (~0.9 microns).

Non-detections can constrain planetary albedos and re-radiation factors.

Abstract

Very hot Jupiters (VHJs) are defined as Jupiter-mass extrasolar planets with orbital periods shorter than three days. For low albedos the effective temperatures of irradiated VHJs can reach 2500-3000 K. Thermal emission from VHJs is therefore potentially strong at optical wavelengths. We explore the prospects of detecting optical-wavelength thermal emission during secondary eclipse with existing ground-based telescopes. We show that OGLE-TR-56b and OGLE-TR-132b are the best suited candidates for detection, and that the prospects are highest around z'-band (~0.9 microns). We also speculate that any newly discovered VHJs with the right combination of orbital separation and host star parameters could be thermally detected in the optical. The lack of detections would still provide constraints on the planetary albedos and re-radiation factors.