Geometric albedos at short optical wavelengths for the hot Jupiters WASP-43b, WASP-103b, and TrES-3b

TL;DR

This study uses ground-based telescopes to measure the reflection properties of three hot Jupiters at short optical wavelengths, finding low geometric albedos and demonstrating the feasibility of such observations from the ground.

Contribution

It presents the first ground-based measurements of geometric albedos for these exoplanets at blue optical wavelengths, expanding observational capabilities.

Findings

Derived low geometric albedos ranging from 0 to 0.18

Demonstrated ground-based detection of exoplanet reflection at short wavelengths

Showed potential for wavelength-resolved reflection studies with small telescopes

Abstract

The largest and most close-in exoplanets would reflect enough star light to enable its ground-based photometric detection under the condition of a high to moderate albedo. We present the results of an observing campaign of secondary eclipse light curves of three of the most suitable exoplanet targets, WASP-43b, WASP-103b, and TrES-3b. The observations were conducted with meter-sized telescopes in the blue optical broadband filters Johnson B and Johnson V. We do not detect a photometric dimming at the moment of the eclipse, and derive a best-fit eclipse depth by an injection-recovery test. These depth values are then used to infer low geometric albedos ranging from zero to 0.18 with an uncertainty of 0.12 or better in most cases. This work illustrates the potential of ground-based telescopes to provide wavelength-resolved reflection properties of selected exoplanets even at short optical wavelengths, which otherwise are only accessible by the Hubble Space Telescope.