Scientists observed a tragic "kiss" between two stars that are most likely heading for disaster.
Using the European Southern Observatory's Very Large Telescope (VLT) the researchers spotted two massive double stars so close together that they touch. The stars will most likely either coalesce to create a single giant star or transform into a binary black hole.
The stars are located in the extreme system VFTS 352 from the Tarantula Nebula. This region is the most active star nursery in the nearby universe. VFTS 352 is composed of two very hot, bright and massive stars. These stars are so close that their surfaces overlap and form a "bridge," and are the hottest and largest known "overcontact binaries." Stars such as these are believed to be crucial for the evolution of galaxies because they are the main producers of elements such as oxygen.
Double stars are also linked to exotic behavior such as the phenomenon of "vampire stars," in which a smaller companion star sucks the matter from the surface of its larger companion. In the case of VFTS 352 however, both stars are almost identical in size. This means material is not sucked from one to the other, but rather shared between the two.
"The VFTS 352 is the best case yet found for a hot and massive double star that may show this kind of internal mixing," said lead author Leonardo A. Almeida of the University of São Paulo, Brazil. "As such it's a fascinating and important discovery."
The researchers believe the tight-knit stars will either merge to create a "magnetic, gigantic single star" or long-duration gamma-ray burst, which is one of the most powerful types of explosion in the universe. There is also a possibility the stars will remain compact enough to avoid merging.
"This would lead the objects down a new evolutionary path that is completely different from classic stellar evolution predictions. In the case of VFTS 352, the components would likely end their lives in supernova explosions, forming a close binary system of black holes. Such a remarkable object would be an intense source of gravitational waves," said lead theoretical astrophysicist in the team, Selma de Mink of University of Amsterdam.
Proving the existence of this type of evolutionary path would be considered an "observational breakthrough," and the findings have already provided fascinating insights into the evolutionary processes of massive overcontact binary star systems.
The findings were published in a recent edition of the Astrophysical Journal.
