This week’s seminar will be by Nienke van der Marel (Leiden) on
“Novel views on planet formation and dust evolution: connecting protoplanetary disk demographics with exoplanets, debris disks and exoplanet atmospheres.“
The Teams link can be found iat the bottom of this post. Please get in touch if there are any access issues (ab520).
Abstract: Structures such as gaps and rings in ALMA observations of protoplanetary disks have long been hailed as signposts of planet formation. However, a direct link between exoplanets and protoplanetary disks remained hard to identify. Recent work has shown that gapped disks retain high millimeter-dust masses up to at least 10 Myr, whereas the majority of disks is compact and decreases its dust mass rapidly. This can be understood when considering dust evolution, where dust traps prevent radial drift in the gapped disks. The fraction of gapped disks shows a stellar mass dependence, and I propose a scenario linking this dependence with that of giant exoplanet occurrence rates. It is shown that there are enough exoplanets to account for the observed disk structures if gapped disks are caused by exoplanets more massive than Neptune, under the assumption that most of those planets eventually migrate inwards. On the other hand, the known anti-correlation between transiting super-Earths and stellar mass implies those planets must form in the compact disks, consistent with those exoplanets forming through pebble accretion in drift-dominated disks. The gapped disks are also the most likely progenitors of debris disks around older stars, which has important consequences for disk evolution timescales. Finally, I will show that dust traps and radial drift may play a crucial role in regulating the chemical composition of disks, which sets the C/O ratio of exoplanet atmospheres as traced in the coming years with the James Webb Space Telescope.
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