14 DAY TRIAL // Astronomers announce the discovery of four so-called impossible stars, binary systems where the two stellar objects orbit so close to each other that they should theoretically merge. Yet, somehow, they avoid this fate altogether, posing a challenging mystery for experts in the process.
When the first such stellar pair was observed, scientists thought they were seeing a fluke of nature. Now that four more systems were discovered, the situation is bound to change, since it would appear that the phenomenon is significantly more widespread than first thought.
The discovery could very well force astronomers to rewrite some of the current wisdom associated with understanding binary systems. The new discoveries were made using the United Kingdom Infrared Telescope (UKIRT), in Hawaii.
In these “impossible” systems, the two stars orbit each other in just four hours. Previously, scientists had thought that stellar orbits which orbit one another in less than five hours cannot remain stable, and that the two objects must eventually collide, Space reports.
The situation is made even more interesting by recent discoveries, which suggest that no less than half of the 100 billion stars in the Milky Way exist in a binary system. Therefore, chances of finding such weird pairs are very high.
The new investigation covered a total of several hundreds of thousands of stars, over a 5-year period. Astronomers were looking for subtle variations in brightness coming from the targets objects. Extra attention was paid to binaries composed of red dwarfs.
These stars are roughly 1,000 times dimmer than the Sun, and 10 times smaller. Surveys indicate that they are the most common type of stellar objects in the Universe. Oftentimes, astronomers cannot see them because they are too dim for optical observatories to pick up.
“To our complete surprise, we found several red dwarf binaries with orbital periods significantly shorter than the 5 hour cut-off found for Sun-like stars, something previously thought to be impossible,” researcher Bas Nefs explains.
“It means that we have to rethink how these close-in binaries form and evolve,” adds the Leiden Observatory astronomer. He was also the lead author of a new study detailing the findings, which appears in the latest issue of the journal Monthly Notices of the Royal Astronomical Society.