Multi-filter transit observations of WASP-39b and WASP-43b with three San Pedro M\'artir telescopes

TL;DR

This study presents multi-filter photometric observations of exoplanets WASP-39b and WASP-43b using three telescopes at San Pedro Mártir, refining their orbital and physical parameters and demonstrating the utility of multi-filter defocused photometry.

Contribution

First multi-filter photometry of WASP-39b and WASP-43b with three telescopes, improving orbital and physical parameters and demonstrating new observational techniques.

Findings

WASP-39b period is slightly longer than previously reported.

WASP-43b radius in the i filter is larger than earlier measurements.

No evidence of period variations in WASP-43b.

Abstract

Three optical telescopes located at the San Pedro M\'artir National Observatory were used for the first time to obtain multi-filter defocused photometry of the transiting extrasolar planets WASP-39b and WASP-43b. We observed WASP-39b with the 2.12m telescope in the U filter for the first time, and additional observations were carried out in the R and I filters using the 0.84m telescope. WASP-43b was observed in VRI with the same instrument, and in the i filter with the robotic 1.50m telescope. We reduced the data using different pipelines and performed aperture photometry with the help of custom routines, in order to obtain the light curves. The fit of the light curves (1.5--2.5mmag rms), and of the period analysis, allowed a revision of the orbital and physical parameters, revealing for WASP-39b a period ($4.0552947 \pm 9.65 \times 10^{-7}$ days) which is $3.084 \pm 0.774$ seconds larger than previously reported. Moreover, we find for WASP-43b a planet/star radius ($0.1738 \pm 0.0033$) which is $0.01637 \pm 0.00371$ larger in the i filter with respect to previous works, and that should be confirmed with additional observations. Finally, we confirm no evidence of constant period variations in WASP-43b.