Artist's impression of a white dwarf. Sciencepics/Shutterstock.com
An ancient sun that has survived over the period of time so long, that its outmost layer is now composed almost completely of pure oxygen. When stars, with less than 10 times the mass of our Sun, come close to end of their lifespan, they lose their outer layers and turn into what are called white dwarfs. Under strong gravity, the heaviest elements incline into the star's thick core, while lighter elements for instance hydrogen and helium rise to the surface. That what’s happen according to our current knowledge.
But this newly discovered star, called SDSS J124043.01+671034.68, doesn’t follow this trend, with astronomers noticing that its outer atmosphere is basically greater than 99.99 percent oxygen. Only traces of other elements have been identified, comprising neon, magnesium, and silicon, but as for the hydrogen and helium you'd suppose to find controlling the surface, there's no sign.
It's an enigma for the group of astronomers that discovered it, led by Souza Oliveira Kepler from the Federal University of Rio Grande do Sul in Brazil. He told William Herkewitz at Popular Mechanics, "What happened to all these light elements? How did they all get stripped away?"
Astronomers have long considered that elements being stripped from a star's exterior over time could be a possibility. If that's exactly what's took place here, SDSS J124043.01+671034.68 (or 'Dox' as the scientists have nicknamed it) is the first indication of the phenomenon taking place. But how did the other elements get stripped away? Nobody knows for sure.
This oxygen-dominated star is a true one-of-a-kind in terms of the solar bodies we currently know about, being the only star amid some 32,000 white dwarfs with such a perfect oxygen atmosphere.