Astrolunch: Uri Malamud (Technion)

Date: 
Tue, 04/02/2020 - 12:30 to 13:30

Title:
How (and what) can we learn about exo-solar moons, dwarf and minor planets.
Abstract:
Exomoons orbiting terrestrial or super-terrestrial exoplanets have not yet been discovered; their possible existence and properties are therefore still an unresolved question. I will present results from a recent study about the collision-formation of massive exomoons, and discuss the plausibility of detecting them currently or in the future. We are also able to infer the existence of exo-solar moons, dwarf and minor planets from the observation of polluted white dwarf atmospheres, which probe their bulk composition. Small planetary objects with tidal crossing orbits disrupt around the white dwarf and form a disk of debris, which later accrete onto the white dwarf and pollute its atmosphere. Progress in the last decade, has shown this material to be typically dry, i.e., with terrestrial-like chemical composition and lacking in water. l will discuss results from a series of numerical studies which examine whether water-bearing small planetary objects have the potential to retain their water, as they undergo thermal, physical, chemical and orbital evolution during the high luminosity stellar evolution phases of their host stars. If time permits I will talk briefly about new hybrid approaches for modeling the aforementioned tidal disruptions and generating debris disks.