Odd white dwarf found with mostly oxygen atmosphere

Something stripped dead star of its hydrogen and helium, providing rare peek into its core

White dwarf and Sirius

RARE AIR  A newly discovered white dwarf has an atmosphere unlike any other — it’s loaded with oxygen. Hydrogen and helium dominate the atmospheres of more typical white dwarfs, such as this one (lower left) snuggled up to Sirius (center), the brightest star in the night sky.

NASA, ESA, H. Bond/STScI, M. Barstow/University of Leicester

White dwarfs — the exposed cores of dead stars — are the last place astronomers expected to find an oxygen atmosphere.