By Michael Allen
Scientists have made an exciting leap in astronomy by using NASA’s IXPE (Imaging X-ray Polarization Explorer) to study a white dwarf star for the first time. This incredible feat involves examining a star named EX Hydrae, which sits about 200 light-years away in the constellation Hydra. Thanks to IXPE’s unique ability to measure X-ray polarization, researchers are unlocking new insights into how energetic binary star systems work.
In 2024, IXPE trained its focus on EX Hydrae for nearly a week. A recent study published in the Astrophysical Journal highlights these findings. This research was led by experts from the Massachusetts Institute of Technology (MIT), with contributions from institutions like the University of Iowa and East Tennessee State University.
So, what is a white dwarf? It’s a star that has exhausted its hydrogen fuel but lacks the mass to go out with a bang like a supernova. These remnants are incredibly dense, about the size of Earth yet weighing as much as our Sun.
EX Hydrae isn’t alone; it’s part of a binary system with a companion star. Gas is consistently pulled from this companion and falls onto the white dwarf. How that gas interacts with the white dwarf depends largely on its magnetic field. In the case of EX Hydrae, the magnetic field isn’t strong enough to concentrate all the matter at the poles, but it still collects enough mass to form an accretion disk. That’s why it’s classified as an “intermediate polar.”
In this system, as the material spirals toward the white dwarf, temperatures soar to millions of degrees Fahrenheit. This extreme heat causes gas to collide and create enormous columns, radiating high-energy X-rays—perfect for IXPE’s observations. Sean Gunderson, an MIT scientist and lead author of the study, explained, “With IXPE, we measured the height of the accreting column to be nearly 2,000 miles—making this a significant advancement over previous methods.” He emphasized how IXPE’s polarimetry gives researchers a clearer view of these cosmic phenomena.
The data gathered from EX Hydrae will be invaluable for understanding other energetic binary systems. This information could broaden our overall knowledge of how stars interact in space.
IXPE is part of a larger collaboration between NASA and the Italian Space Agency, involving partners from 12 different countries. The mission aims to gather groundbreaking data that reshapes our understanding of celestial objects, making significant contributions to the field of astrophysics. To explore more about IXPE’s ongoing mission, check out the official page: NASA IXPE Mission.
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Astrophysics, IXPE (Imaging X-ray Polarimetry Explorer), Marshall Astrophysics, Marshall Space Flight Center
