A team of Brazilian and German astrophysicists has found a white dwarf with an almost pure oxygen atmosphere. It is the first to be found and forces us to rethink the studies on the evolution of stars . The study has been published in the journal Science.
What are white dwarfs?
White dwarfs transform into a class of stars with a high density when they approach the end of their existence by expelling their outermost layers into space, also having a relatively small size (10 times less mass than our Sun ). At this point, they become what we call white dwarfs. This one in particular has been baptized as SDSS J124043.01 + 671034.68.
Its high gravity – due to its high density – causes the lightest chemical elements such as helium and hydrogen to rise to the surface of the star, leaving the heavier elements such as oxygen underneath.
However, while examining data from the Sloan Digital Sky Survey (SDSS), the scientists identified SDSS J124043.01 + 671034.68, as a white dwarf with an absence of light elements and a practically pure oxygen layer (with only a few traces of neon and magnesium).
“The fact that hydrogen or helium are not observed is surprising. SDSS J124043.01 + 671034.68 provides a rare observational proof of the evolutionary paths towards white dwarfs “, say the authors who will continue to investigate the white dwarf to discover why it has lost that outer layer of light elements and is, therefore, so exceptional.
