Germany: Astronomers find 'strange' new type of star covered in helium burning ashes

In Germany, a team of astronomers has made an unexpected discovery of a new type of star that appears to defy star formation rules. A press statement was released which said that the majority of stars have hydrogen and helium on their surfaces, however, these new stars discovered by astronomers have carbon and oxygen on their surfaces.

Klaus Werner, a professor at the University of Tubingen and the leader of the team that identified this new type of star said that normally, they would expect stars with the surface compositions to have burned all of the helium in their cores and be on their way to becoming white dwarfs. The study of the researcher was published in the Monthly Notices of the Royal Astronomical Society, which says that the size and temperature of these new stars suggest that helium is still burning steadily at the core.

The finding was unexpected

The stars were discovered as part of a programme that looked for short-lived, hot stars known as subdwarfs in order to learn more about a star's closing phases of existence, according to CTV News. Researchers expected to find mostly stars that had completed their helium fusion in their cores and were on their way to becoming a white dwarf. As a result, the finding of these hot subdwarfs covered in helium-burning ash was unexpected.

In a press release, Miller Bertolami of the Institute for Astrophysics of La Plata stated that they believe the stars observed by the German colleagues may have evolved in a very uncommon type of stellar merger event between two white dwarf stars. Bertolami also said that white dwarf mergers typically do not result in the production of carbon and oxygen-rich stars. However, they believe that in binary systems with very particular masses, a carbon and oxygen-rich white dwarf may be disturbed and wind up on top of a helium-rich white dwarf, resulting in the birth of these stars.

Simulations were run to evaluate if this merger would work

Bertolami is the author of a follow-up paper, which presents a possible explanation for the unusual stars. The shortened orbits of white dwarfs can cause them to collide when they are in near binary systems. The second paper also suggests that simulations were run to evaluate if this merger would work, and the calculations revealed that such a merger may produce a star with similar characteristics.

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