Detection of 27 candidate circumbinary planets through apsidal precession of eclipsing binaries observed by TESS
Most circumbinary planets have been discovered by their transits, limiting our understanding of such systems to those with mutually coplanar architectures. This bias makes it difficult to infer the true circumbinary planet population, highlighting the need for alternative detection methods that do not rely on transits. In this work, we explore one such approach by leveraging apsidal precession as a dynamical signature of planetary companions. We analyse TESS photometry of a sample of 1590 eclipsing binaries from the Gaia DR3 Catalogue of Eclipsing Binary Candidates to identify systems exhibiting measurable apsidal precession that cannot be explained by general relativistic, tidal, or rotational effects alone. These excess precession signals point to the presence of additional gravitational perturbers and allow constraints to be placed on the masses and orbital separations of potential companions. We present a new set of 27 candidate circumbinary planets identified through this precession-based method, as well as 6 candidate companions with a higher minimum mass. Their inferred properties remain degenerate, as the same dynamical signatures can arise from lower-mass planets at less than 1 AU or from more massive companions on wider, few-AU orbits, reflecting the current uncertainty in characterising these systems. Radial velocities can help break this degeneracy and provide direct confirmation.