Faculty Spotlight
Peter Garnavich
The star system, referred to as J0240, is only the second of its kind on record. It was identified in 2020 as an unusual cataclysmic variable — a binary system consisting of a white dwarf star and a mass-donating red star. Normally, the compact white dwarf star collects the donated gas and grows in mass. In J0240, however, the fast-spinning, magnetic white dwarf rejects the donor’s gas and propels it out of the binary system.
“It takes a rapidly spinning dwarf with a strong magnetic field in order to create a propeller,” said Peter Garnavich, professor of astrophysics and cosmology physics and chair of the Department of Physics at Notre Dame, and lead author of the study that presented evidence of the propeller system. “Normally, gas coming off of the donor star will land on the white dwarf. That’s as common as sand on a beach. But in a magnetic propeller, the gas is ejected from the binary in a wide spiral pattern — like a lawn sprinkler watering your yard.”
Full story here.
