A star with an atmosphere made of almost entirely of pure oxygen has been discovered. It is described in a paper published in the journal Science.
The new kind of star was hitherto thought to be theoretical only. Named SDSS J124043.01+671034.68 (and commonly being called Dox), has deviated from the general rule that small stars (less than ten times the Sun’s mass) follow: instead of shedding its outer layers and becoming a white dwarf when dying, it formed an outer atmosphere that is 99.99% oxygen with traces of other elements such as neon, silicon, and magnesium, with no sign of hydrogen and helium. Another puzzling aspect of this discovery is that the latter two (hydrogen and helium) are of the lightest elements, and it does not make sense as to where they disappeared.
It thus seems that elements have been stripped off the surface of the star. If this is so, this would be the first time such an occurrence has been discovered.
The scientists behind the discovery, led by Kepler de Souza Oliveira, suggest that Dox might be in a binary star system whereby the other star would have stripped away some of its elements from its atmosphere. Another possibility mentioned is that carbon burning at Dox’s core might have flared outwards, thereby getting rid of the lighter elements.
Since Dox is the first of its kind to be identified, more studies have to be done to understand how it works.