Oral Abstract

Oral Contribution (O0.10) Dirk van Dam (Universiteit Leiden)

BeyonCE (Beyond Circular Eclipsers) - an Exo-Ring Light Curve Solver

Long baseline photometric surveys of the sky have revealed the wide variety of phenomena that cause the brightness of stars to fluctuate. Among many others, astronomers have learned about stellar activity, modulated by the rotation of the star, pulsations, flares, and the transits of exo-planets, exo-comets, and dust clumps within the protoplanetary disk. Light curves reveal the intricate details of a stellar/planetary system and the planet-hunting community has developed many tools to efficiently and effectively recover exoplanet transits from vast databases of archival data. Instead, we focus on the light curves that are ignored by planet-hunting code and try to develop an understanding of the mechanics behind long eclipses (several days/weeks/months) that show significant sub-structure, varying transit depths (both in time and colour), signs of asymmetry and do not necessarily repeat in the data that has as of yet been collected. We find that these systems can be described by the transits of large circumplanetary disks that have evolved into exo-ring systems due to the natural evolution of said disks and/or the carving out of the disk due to the formation of exomoons. BeyonCE (Beyond Common Eclipses) is a python package designed to explore the large parameter space that characterise the transits of circumplanetary disks (disk radius, inclination, tilt), that are broken-up into exo-ring systems (anchor body radius, inner and outer ring radii and the respective ring opacities), stellar parameters (size and limb-darkening) and orbital parameters (transverse velocity, impact parameter and the time of closest approach). It is done by efficiently reducing the size of the parameter space based on the eclipse duration, measured gradients and Hill sphere consideration. The reduced sub-space is then explored in detail to determine viable exo-ring solutions for the input light curve.