The members of the LP 413-53AB system are so close that it takes just 17 hours to revolve around each other.
Previously, astronomers had only detected three short-period ultracool dwarf binary systems, all of which are relatively young — up to 40 million years old.
LP 413-53AB, also known as 2MASS J03505737+1818069, is estimated to be billions of years old, but has an orbital period that is at least 3 times shorter than the all ultracool dwarf binaries discovered so far.
“It’s exciting to discover such an extreme system,” said Dr. Chih-Chun ‘Dino’ Hsu, an astrophysicist with the Center for Interdisciplinary Exploration and Research in Astrophysics at Northwestern University and the Center for Astrophysics and Space Science at the University of California, San Diego.
“In principle, we knew these systems should exist, but no such systems had been identified yet.”
Dr. Hsu and colleagues first discovered LP 413-53AB, which is located 120 light-year away in the constellation of Taurus, while exploring archival data.
They then obtained high-resolution near-infrared spectra of the binary system using the Near-InfraRed SPECtrometer (NIRSPEC) on the Keck II telescope at the W.M. Keck Observatory.
“When we were making this measurement, we could see things changing over a couple of minutes of observation,” said Professor Adam Burgasser, an astronomer at the Center for Astrophysics and Space Science at the University of California, San Diego.
“Most binaries we follow have orbit periods of years. So, you get a measurement every few months. Then, after a while, you can piece together the puzzle.”
“With this system, we could see the spectral lines moving apart in real time. It’s amazing to see something happen in the universe on a human time scale.”
The observations show that the distance between the two stars is about 1% of the distance between the Earth and the Sun.
“This is remarkable, because when they were young, something like 1…
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