Monday, December 01, 2025 at 3:30 pm

JILA auditorium

Raluca Rufu , SWRI

"Origin of compact exoplanetary systems during disk infall"

Abstract:

A surprising discovery has been compact systems of Earth to super- Earth-sized planets. While compact systems are common, their origin is debated. A prevalent assumption is that compact systems formed after the infall of gas and solids to the circumstellar disk ended. However, observational evidence suggests accretion may commence earlier. We propose that compact systems are surviving remnants of planet accretion during the end stages of infall. In disk regions undergoing infall, a planet's mass is regulated by a balance between growth due to the supply of solids, and inward gas-driven orbital migration that becomes faster as the planet grows, replicating the intra-system planetary-size-similarly. We show that infall-produced planets can survive until the gas disk disperses and migration ends, and that the mass of surviving compact systems is regulated to between a few x 10^-5 and 10^-4 stellar mass. This provides an explanation for the remarkably similar mass ratios of known compact systems.

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