Peter McGill, Lawrence Livermore National Laboratory
When
Refreshments served at 3:00 pm in the 3rd floor Atrium.
TAP Computation & Data Initiative Special Seminar
Peter McGill, Lawrence Livermore National Laboratory
Visit Dates: Nov 23 - 26
Title: The Challenges of Detecting Gases in Exoplanet Atmospheres
Abstract: The field of exoplanet characterization is now answering fundamental questions on planetary climate, composition, and formation, providing context for understanding our own solar system. The unprecedented precision and spectral resolution of the James Webb Space Telescope have allowed for the characterization of the atmospheres of planets ranging from ultrahot Jupiters, to lukewarm Neptunes, to terrestrial-sized and potentially habitable worlds, transitioning the field from being data-limited to model-limited. As a result, apparent detections of trace gases risk being artifacts of incomplete modeling rather than robust identification of atmospheric constituents, especially in the low signal-to-noise regime. I will illustrate these challenges using the sub-Neptune K2-18b, and challenge the recent, astonishing claims of a potential biosignature in its atmosphere.
Bio: Peter McGill is a Research Scientist at Lawrence Livermore National Laboratory (LLNL) specializing in astronomy at the intersection of new statistical techniques, large astronomical datasets, and high-performance computing. His current research focuses on robustly interpreting exoplanet transmission spectroscopy from the James Webb Space Telescope (JWST) to better understand the underlying population properties of exoplanets. Peter is currently the PI of a computing grand challenge program allocating 50 million CPU hours to develop the next generation of exoplanet atmospheric models for JWST. He is a science team contributor for the upcoming NASA Pandora Small Satellite mission and serves as a member of the astrometry working group for the Roman Space Telescope.
Prior to joining LLNL, Peter held a postdoctoral position at the University of California, Santa Cruz, where he worked on scalable transient survey infrastructure. He received his PhD in Astronomy from the University of Cambridge and an MSci in Theoretical Physics from University College London. During his PhD, Peter led a team that directly measured the mass of a single, isolated white dwarf for the first time.