Astrophysicists discovered the closest ultra-cool binary stars ever observed. Their close proximity almost fooled the team as they look like a single star. As per Universe Today, the two stars are so close that a year in them only lasts for 20.5 hours, which is the amount of time it takes them to evolve around each other.
Those stars are also older than similar systems and are ultra-cool dwarf stars that are abundant in the galaxy. They have low masses that they emit infrared light so scientists have to use infrared telescopes to see them.
Closest Binary Pair Ever Found
The team of astrophysicists, led by astrophysicist Chih-Chun "Dino" Hsu from Northwestern University, presented their findings during the 241st Meeting of the American Astronomical Society in Seattle.
The binary stars are interesting objects because they are so close together and they are the first of their kind to be observed. They named the binary system LP 413-53AB.
Hsu said in a press release that it is exciting to discover such a star system. Scientists have theorized about this kind of binary dwarf stars, knowing that they exist, but no such system yet was ever identified.
Nature's extremes play a vital role in calibrating existing theoretical models, and low-mass binaries are no exception. Only three short-period, ultra-cool binaries were known to astronomers prior to discovering LP 413-53AB. The pair was discovered in archive data by the study team when they were sifting through data with Hsu's program, which models stars based on their spectral data.
However, in those earlier photographs, the stars occurred to be aligned and appeared like a single star. For a tight binary pair like this, the chances of that happening are considerable.
The team thought the data was strange so they used the Keck Observatory to investigate the star more closely. The measurements revealed that the light curve altered so swiftly that two stars must exist. They concluded they had discovered the nearest binary pair ever discovered.
How Close Are the Binary Stars?
Their observations at the Keck Observatory helped them observe the binary stars orbiting each other, Science Daily reports. They started observing it on March 13, 2022, then followed up with more observations in July, October, and December.
The team noted seeing things changing over a couple of minutes of observations. They find it odd as most binaries scientists follow have orbit periods of years, which means they could get a measurement every few months. But LP 413-53AB is different as they could easily see its spectral lines moving apart in real-time, which is an amazing feat in the universe on a human time scale.
They confirmed Hsu's prediction that the distance between the two stars is approximately 1% of the distance between Earth and the Sun. To compare it to the planets in the Solar System, it means the binary stars are closer than Jupiter and one of its moons. They believe that the stars would have been on top of each other when they were young or about 1 million years old.
The team thinks the stars could have migrated toward each other as they evolve or that an outside force could have made them come together. They recommend more observations be conducted to answer further questions.
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