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