Charlotte Smith-Perez

Western University

Charlotte Smith-Perez is a second year astrophysics master’s student at Western University, working under the supervision of Professor Els Peeters. Her project focuses on studying the infrared emission of organic molecules in a planetary nebula using JWST mid-infrared observations.

Polycyclic Aromatic Hydrocarbons (PAHs) are a family of organic molecules composed of benzene rings fused together in different configurations and sizes. These molecules are abundant throughout the Universe, found in nebulae, the interstellar medium, proto-planetary disks, star-forming regions and galaxies. PAHs are detected via their characteristic infrared vibrational modes. Variations in PAH emission is caused by the response of the PAH population (in terms of charge, size, structure) to changing physical conditions (temperature, density, radiation field) of their host environment. PAH emission therefore serves as a diagnostic tool to probe the conditions of their environment. The PAH population also influences the conditions within their host environment, serving as a primary heating source for the interstellar medium and regulating chemical abundances. Understanding PAH formation and evolution is therefore critical to unraveling the physical and chemical pathways that govern star- and planet-formation.

Charlotte’s project investigates the PAH population in NGC7027 – a young, hot, carbon-rich planetary nebula. PAHs are formed in the stellar evolutionary phase prior to the planetary nebula phase, therefore making NGC7027 an ideal laboratory to characterize PAHs shortly after their birth. The project utilizes JWST MIRI spectral data to examine how PAH properties vary across distinct regions of NGC 7027 and link these variations to local physical conditions. Preliminary results reveal unique PAH spectral profiles not previously observed and significant spectral variations across the nebula. This project sheds light on the lifecycle of PAHs, connecting their evolution to interstellar enrichment and star- and planet-formation in the nearby Universe.