A SuperWASP search for additional transiting planets in 24 known systems

TL;DR

This study used SuperWASP data to search for additional transiting planets in 24 known systems, finding no new planets but assessing detection capabilities and confirming stellar rotation in one system.

Contribution

The paper introduces a method to evaluate detection efficiency for additional planets using Monte Carlo simulations and refines stellar rotation period measurements.

Findings

No additional planets detected in the studied systems.

Detection probability > 50% for Saturn-sized planets with ~10-day periods.

Confirmed stellar rotation period of WASP-10 as 11.91 days.

Abstract

We present results from a search for additional transiting planets in 24 systems already known to contain a transiting planet. We model the transits due to the known planet in each system and subtract these models from lightcurves obtained with the SuperWASP survey instruments. These residual lightcurves are then searched for evidence of additional periodic transit events. Although we do not find any evidence for additional planets in any of the planetary systems studied, we are able to characterise our ability to find such planets by means of Monte Carlo simulations. Artificially generated transit signals corresponding to planets with a range of sizes and orbital periods were injected into the SuperWASP photometry and the resulting lightcurves searched for planets. As a result, the detection efficiency as a function of both the radius and orbital period of any second planet, is calculated. We determine that there is a good (> 50 per cent) chance of detecting additional, Saturn-sized planets in P ~ 10 d orbits around planet-hosting stars that have several seasons of SuperWASP photometry. Additionally, we confirm previous evidence of the rotational stellar variability of WASP-10, and refine the period of rotation. We find that the period of the rotation is 11.91 \pm 0.05 d, and the false alarm probability for this period is extremely low (~ 10^{-13}).