This Week's Discoveries | 9 June 2020
- Tuesday 9 June 2020
- Kaltura Live Room (see link below)
When do baby planets start to form?
Join the lecture in Kaltura Live Room
Dr. Melissa McClure is an assistant professor at the Leiden Observatory. She received her PhD in astrophysics from the University of Michigan in 2014, followed by a post-doctoral fellowship at the European Southern Observatories (2014-2017) and a Marie Curie fellowship at the University of Amsterdam (2017-2019). She joined Leiden University in fall 2019.
McClure studies the composition and structure of protoplanetary disks using near-, mid-, and far-infrared spectroscopy of gas and dust. Her research focuses on using the disk structures and gas composition to trace how the dust composition evolves during planet formation. The knowledge produced by such studies will be used to create models for the compositions of exoplanet populations and how terrestrial planets acquire the atomic and molecular ingredients for life.
'During the collapse of a cold, dense molecular cloud to form a young star, planets form as a by-product within "protoplanetary disks", structures which channel gas and dust onto their central stars. In our own solar system, evidence suggests that planetary embryos formed early, with Jupiter by 1 Myr and Earth by 3.8 Myr. Planetary compositions are determined in part by when each planet forms. However, it is difficult to see planets forming within protoplanetary disks directly, since they are faint and form surrounded by obscuring dust.
'I propose an indirect method to infer the formation timescales and composition of planetary embryos by comparing the composition of the gas feeding the young star at the center of the disk with the composition of the stellar surface itself. Using this technique on a well-studied star-disk system, I show that the initial stages of planet formation must occur early and fast, within 10,000-100,000 years after the initial formation of the central star. This result is consistent with the solar system's timescales, and it observationally confirms a trend towards seeing signatures of already-formed planets in younger and younger disks.'