High-precision photometry by telescope defocussing. VI. WASP-24, WASP-25 and WASP-26

TL;DR

This study uses telescope-defocussing to obtain high-precision photometry of transiting exoplanets WASP-24, WASP-25, and WASP-26, refining their physical and orbital parameters with minimal contamination.

Contribution

It provides improved measurements of the physical properties and orbital parameters of three exoplanet systems using defocussed photometry and confirms the absence of nearby contaminant stars.

Findings

High-precision light curves with 0.5-1.2 mmag scatter.

Refined physical and orbital parameters consistent with previous studies.

No faint contaminant stars detected near the targets.

Abstract

We present time-series photometric observations of thirteen transits in the planetary systems WASP-24, WASP-25 and WASP-26. All three systems have orbital obliquity measurements, WASP-24 and WASP-26 have been observed with Spitzer, and WASP-25 was previously comparatively neglected. Our light curves were obtained using the telescope-defocussing method and have scatters of 0.5 to 1.2 mmag relative to their best-fitting geometric models. We used these data to measure the physical properties and orbital ephemerides of the systems to high precision, finding that our improved measurements are in good agreement with previous studies. High-resolution Lucky Imaging observations of all three targets show no evidence for faint stars close enough to contaminate our photometry. We confirm the eclipsing nature of the star closest to WASP-24 and present the detection of a detached eclipsing binary within 4.25 arcmin of WASP-26.