Scientists have discovered a new bizarre type of star with atmosphere made almost entirely of oxygen 99.9% pure oxygen, the most oxygen-rich atmosphere in the known universe. According to the theories, such star should exist but researchers have never identified it until now.
White dwarf star are relatively small stars, slightly bigger than the Earth. They are born when a low or medium mass star (with masses from about 0.07 ÷ 10 that of the sun) runs out of hydrogen to fuse and then it starts to collapse inward on itself. The star will swell up into red giants, eventually shedding its outer layers and forms a planetary nebula. The core that is left behind will be a white dwarf. White dwarfs contain approximately the mass of the sun while its volume is comparable to that of Earth, which makes it incredibly dense, beaten out only by neutron stars and black holes.
With a surface gravity of 100,000 times that of Earth, such high gravity makes heavier atoms in its atmosphere such as carbon and oxygen sink, and the lighter ones like hydrogen and helium remain at the surface. Some white dwarfs have almost pure hydrogen or helium atmospheres. But a white dwarf with almost pure oxygen atmosphere is extremely unusually, so rare that’s possible only in theory.
Now for the first time, using data from the Sloan Digital Sky Survey (SDSS) and the Kepler telescope, researchers have spotted one of these bizarre dying stars. Named SDSS J124043.01+671034.68, is located about 1,200 light-years away in the constellation Draco, has no hydrogen or helium at its surface. It is surrounded by an atmosphere of mostly oxygen, researchers report in the April 1 Science.
We only found one, so it is a rare event,
says de Souza Oliveira Filho ~ coauthor of the study published in Science.
every theory must be able to explain all events, even the rare ones.
This discovery is so surprising that makes astronomers scratching their heads. There is no hydrogen and helium in the atmosphere of the white dwarf in question, only oxygen. So how is that possible? Researchers aren’t sure, but they think that some kind of event has caused the two elements to disappear, making oxygen the lightest element in the star’s atmosphere.
We don’t make models of things we don’t know exist,
But now that we know this star exists, we have to calculate the model for it.
Some scientists think that SDSS J124043.01+671034.68 (I know its annoying name, actually the dwarf star is also nicknamed “Dox”) was part of a binary system, then the 2 stars merged together, causing an explosion that ejected the hydrogen and helium.
We don’t have a calculation that shows [a binary merger] happened, but that’s the only explanation that I can think of,
It must have come from a binary system.
Experts believe this finding could challenge the theory of single stellar evolution and provide a critical link for some types of supernovae discovered during the last decade, the American Association for the Advancement of Science said in a statement.
Researchers will continue monitoring this star to understand how and why it’s atmosphere became full of oxygen.
This chemical composition is unique among known stars and must arise from an extremely rare process,
said Boris Gänsicke ~ not involved in the study.
It’s a new class of star,
said Andrew Vanderburg ~ also not involved in the study.
We don’t understand how it formed, but this is the kind of thing that pushes our field forward, and who knows where it will take us.