Detection and Characterization of Circumbinary Planets Around TESS Eclipsing Binaries

Unraveling the characteristics of circumbinary planets (CBPs) is of fundamental value in exoplanetary astronomy as this new class of bodies enable researchers to address questions regarding the formation, migration, evolution and habitability of planetary systems in a larger context. Thanks to the successful operation of the Kepler and TESS telescopes, 14 such planets have already been detected and some trends seem to have emerged. For instance, the orbits of several of these bodies are close to the boundary of stability, and they all reside between major resonances with their host binaries. It is also widely accepted that currently known CBPs have formed at large distances and migrated to their current orbits, with those close to the stability limit being Neptune-sized or slightly larger.

Despite these advances, some pressing questions still stand. For instance, the efficiency of the formation and migration of CBPs is unknown, and so are their occurrence frequency, orbital architecture, and the population characteristics of their host binaries. To address these questions, a CBP population larger than the current 14 is required. We plan to use a unique observational signature of transiting CBPs, namely, the occurrence of multiple transits during one conjunction, to detect several tens to more than a hundred of these objects. This characteristics of CBPs has been shown to be a powerful detection technique for identifying planets around eclipsing binaries (EBs). We, therefore, plan to apply this technique to the light-curves of 300,000 TESS EBs that are currently available to us. This technique allows for probing planetary periods longer than even the year-long observations of the ecliptic pole, thereby enhancing the science return of TESS and maximizing the long-period, temperate planet yield.

Our proposed project is extremely timely. The 300,000 TESS EB light-curves that will be used in this project is 100 times more than the entire Kepler EB light-curves that were used to detect the current CBPs. With such a large data set, our proposed project will result in the detection of possibly up to an order of magnitude more CBPs which, not only will transform the field from the current realm of individual detections to population statistics, it will also further our knowledge of the formation and dynamical evolution of planets, enabling us to obtain a more expanded view of other planetary systems.