Aarhus Universitets segl

InterCat seminar

Speaker: Melissa McClure Title: "Measuring the chemical evolution of ices from molecular clouds to protoplanetary disks"

Oplysninger om arrangementet


Tirsdag 12. januar 2021,  kl. 11:00 - 12:30



InterCat seminar


Melissa McClure

Leiden Observatory, Leiden University, The Netherlands



Measuring the chemical evolution of ices from molecular clouds to protoplanetary disks.


Planets form at the midplane of the protoplanetary disks surrounding newborn stars. The habitability of a planet is determined in part by the relative amounts of CHON elements at the planet's surface, and these CHONs are most likely delivered through incorporation or delivery of astronomical ices during planet formation. These ices originate in cold, dense molecular cloud cores and chemically evolve as the cores collapse to form protostars surrounded by protoplanetary disks. To understand the relative amounts and degree of complexity of the ices incorporated into comets and planets, we need observational constraints on both the chemical evolution of ices from where they form in clouds to the locations in disks where planets are being formed.


In the first part of the talk, I will describe a cutting-edge Early Release Science (ERS) program, Ice Age (P.I. McClure, over 50 team members world wide) with the upcoming James Webb Space Telescope (JWST) to measure the chemical evolution of ices entering disks. This ERS program will provide the star and planet formation and astrochemistry communities with a non-proprietary dataset of JWST spectra, laboratory data, and chemical models within the 5 months of JWST's science operations. With this dataset, and other GTO JWST programs, we will be able to confirm the amount and complexity of ice formed non-energetically within molecular clouds and test the degree to which energetic processing increases its complexity prior to its incorporation into the disk. These programs will also be able to determine the radial distribution of ices in these disks. Time permitting, in the last part of the talk I will demonstrate a new method for identifying specific locations where ices are "left behind" in protoplanetary disks (McClure 2019; McClure, Dominik, and Kama 2020), possibly by formation of planetesimals. By combining these direct JWST studies of the icy dust input into protoplanetary disks with the direct measurement of material moving out of the disk onto the central star, we can map out where icy material is being retained in a given disk, which is a first, critical step to forming planets.