Transit Timing Variation Measurements of WASP-12b and Qatar-1b: No Evidence for Additional Planets

TL;DR

This study presents new transit observations of WASP-12b and Qatar-1b, refining their system parameters and finding no significant evidence for additional planets through transit timing variations.

Contribution

The paper provides the first comprehensive analysis combining new transit data with literature, reducing uncertainties and constraining the presence of additional bodies in these systems.

Findings

No significant sinusoidal TTVs detected in WASP-12b and Qatar-1b.

Refined system parameters with 40-50% smaller uncertainties.

Transit timing precision limits additional planets to semi-amplitudes of ~35s and ~25s.

Abstract

WASP-12b and Qatar-1b are transiting Hot Jupiters for which previous works have suggested the presence of transit timing variations (TTVs) indicative of additional bodies in these systems - an Earth-mass planet in WASP-12 and a brown-dwarf mass object in Qatar-1. Here, we present 23 new WASP-12b and 18 new Qatar-1b complete (or nearly complete) transit observations. We perform global system fits to all of our light curves for each system, plus RV and stellar spectroscopic parameters from the literature. The global fits provide refined system parameters and uncertainties for each system, including precise transit center times for each transit. The transit model residuals of the combined and five minute binned light curves have a RMS of 183 and 255 parts per million (ppm) for WASP-12b and Qatar-1b, respectively. Most WASP-12b system parameter values from this work are consistent with values from previous studies, but have $\sim$ 40-50% smaller uncertainties. Most of the Qatar-1b system parameter values and uncertainties from this work are consistent with values recently reported in the literature. We find no convincing evidence for sinusoidal TTVs with a semi-amplitude of more than $\sim$ 35 s and $\sim$ 25 s in the WASP-12b and Qatar-1b systems, respectively.