Unusual Binary Stars with a Close Orbital Period Discovered
A team of scientists have discovered four pairs of stars that orbit each other in less than four hours. Credit: University of Hertfordshire /David Pinfield

Scientists have discovered four unusual pairs of stars that orbit each other in less than four hours, according to a new study.

Scientists claim that the orbital period is quite strange because till now they have never found a binary star with such close orbital period.

According to the scientists, more than half of the stars in our milky way are part of a binary system and orbit each other at a certain period, which is more than 5 hours.

They believe that if binary stars orbit very close to each other, they will quickly emerge into one huge star.

The unusual binary stars were discovered while monitoring the brightness of thousands of stars, including red dwarfs by using the United Kingdom Infrared Telescope (UKIRT) in Hawaii.

"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", said Bas Nefs, scientist at the Leiden Observatory, in a statement.

"It means that we have to rethink how these close-in binaries form and evolve," Nefs added.

The study suggested several reasons behind the short orbital period of these stars. One of the reasons is that since stars shrink in size in their lifetime, there is a possibility that their period could also have shrunk; otherwise the stars would have emerged quite long ago.

However, scientists are not sure as to how these orbits could have shrunk so much.

Another possibility is that the magnetic field lines radiating from the cool star companions get twisted and deformed as they orbit each other, generating the extra activity through stellar wind, explosive flaring and star spots. Powerful magnetic activity could apply the brakes to these spinning stars, slowing them down so that they move closer together.

"Without UKIRT's superb sensitivity, it wouldn't have been possible to find these extraordinary pairs of red dwarfs", said David Pinfield, researcher at the University of Hertfordshire.

"The active nature of these stars and their apparently powerful magnetic fields has profound implications for the environments around red dwarfs throughout our Galaxy," he added.