Why does gamma-Cas behave so strangely? Astronomers finally know
After more than a century of head-scratching, astronomers have figured out why the star gamma-Cas acts so strangely.
Using the XRISM spacecraft, scientists discovered that a hidden companion, most likely a white dwarf, is stealing material from gamma-Cas, causing its wild X-ray outbursts.
This solves the puzzle that's baffled experts since 1866.
Discovery helps understand evolution of massive stars in pairs
XRISM's super-precise data confirms what many suspected: it's not just magnetic interactions behind gamma-Cas's behavior, but a compact companion, likely a white dwarf, appears to be at work.
As team leader Yael Naze put it, this helps us better understand how massive stars evolve in pairs.
The discovery also sheds light on other mysterious Be stars and was just published in Astronomy and Astrophysics on March 24, 2026.