David Cohen

David Cohen is a Professor of Astronomy in the Department of Physics and Astronomy at Swarthmore College. He specializes in the study of massive stars, stellar winds, X-ray astrophysics, and exoplanets. Currently on academic leave, he maintains an active research program with undergraduate students and has recently been awarded a $300,000 NASA grant for his work on 'X-ray Spectral Diagnostics of Massive Star Winds and Magnetospheres.'

Dr. Cohen's research primarily focuses on radiation-driven winds of hot, massive stars and their X-ray emission, studied through spectroscopy and modeling. He also investigates magnetic massive stars and their plasma magnetospheres, and has conducted significant work on X-ray emission from pre-main-sequence stars. His research group takes a holistic approach to science, examining both technical aspects and ethical considerations in astronomical research.

His recent publications demonstrate a consistent focus on X-ray diagnostics of stellar winds, particularly in stars like zeta Puppis and HD 93129A. The research shows surprising variability in stellar wind mass-loss rates over time, with one study finding a 40% increase in zeta Puppis's mass-loss rate over 20 years. His work combines observational data from Chandra and XMM-Newton X-ray telescopes with sophisticated modeling techniques.

• $300,000 NASA grant for 'X-ray Spectral Diagnostics of Massive Star Winds and Magnetospheres' (2025)

Dr. Cohen actively mentors undergraduate researchers, with students contributing to numerous publications in journals like Monthly Notices of the Royal Astronomical Society (MNRAS). His students have presented at major conferences including the American Astronomical Society meetings. He collaborates with researchers at NASA Goddard Spaceflight Center and the University of Delaware, providing students with valuable research opportunities. His teaching includes courses such as Astro 126: The Interstellar Medium and Astro 61: Current Problems in Astrophysics.

His research group works with the Peter van de Kamp Observatory's 24-inch telescope for exoplanet research and collaborates with facilities like the Z-Machine at Sandia National Lab for laboratory astrophysics experiments. The group takes an interdisciplinary approach, connecting stellar astrophysics with broader questions about cosmic element cycling and ethical considerations in space science.