LPL Colloquium: Dr. Sarah Peacock

Modeling Exoplanet Host Stars from X-ray to Infrared: Panchromatic Spectra and Their Impact on Planetary Atmospheres

When

Feb. 10, 2026, 3:45 – 4:45 p.m.

Where

Dr. Sarah Peacock
Assistant Research Scientist
NASA Goddard Space Flight Center
University of Maryland

Accurate stellar characterization is critical for interpreting exoplanet atmospheres, particularly in the era of high-precision observations with JWST and the upcoming Habitable Worlds Observatory. In this talk, I will present recent work modeling exoplanet host stars across the electromagnetic spectrum using the PHOENIX atmosphere code. I will begin with JWST/NIRSpec observations of the TRAPPIST-1 system, where we use PHOENIX models to characterize the host star, including its limb darkening, surface heterogeneity, and the effects of a coincident stellar flare. These results provide essential context for interpreting the transmission spectra of TRAPPIST-1 h and b. Next, I will introduce PEGASUS (PHOENIX EUV Grid and Stellar UV Spectra), a web tool in development that will provide synthetic EUV spectra for M and K exoplanet host stars, addressing a key observational gap in exoplanetary system studies. Finally, I will discuss ongoing efforts to construct panchromatic (X-ray to IR) spectra for nearby low-mass and Sun-like stars with directly imageable habitable zones. These projects collectively highlight the importance of stellar spectral models in understanding exoplanetary environments and habitability.

Host: Dr. Travis Barman

To request Zoom Meeting link, contact 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