We just got to see a multiple-star system being born

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Dec 7, 2016

Birthdays are even more epic when a star is born. This isn’t the type of headline you’d see blazing on the front page of some scandalous Hollywood tabloid. Astronomers recently saw something that even the paparazzi wouldn’t be able to get their cameras on: the fireworks of a nascent star system.  

What makes this birthday a real party is that this is the first time scientists have ever actually seen a hot new star fragment into the beginnings of a multiple-star system. Our solar system is a star system, but think of this as if we were orbiting three celestial balls of fire instead of a single sun. While there had been years of theorizing about how unstable gravity in space caused stars to divide like giant space amoebas, there had been no photographic evidence until the Atacama Large Millimeter/submillimeter Array (ALMA) telescope and the Karl G. Jansky Very Large Array (VLA) made it possible to observe. Live.

Think of ALMA and VLA like the camcorder that captured your first moments, except on a much more immense scale. Telescopes like these use radio waves to capture footage of star births and planet formations that may shed light on the enigma of how the ancient universe came into being. Scientists knew they were onto something when it picked up a hazy image of two juvenile stars and a not-too-distant third shining through a gaseous cloud in the L1448 IRS3B system in the Perseus constellation, 750 light-years from Earth.

multiple-star system

An artist's rendering of how a multiple-star system is thought to form.

Stars emerge out of clouds of dust and gases—stardust really is a thing sans the glitter. These clouds eventually collapse into themselves when gravity pulls all these not-so-sparkly particles towards a dense core that attracts even more star stuff. When it grows massive enough and scorching enough to set off thermonuclear reactions (the fusion of atomic nuclei that releases enormous amounts of energy), this glowing orb actually starts to look like a star. What indicates that this is no typical formation is how the disk of so-called stardust spirals. The caramel-y swirl is an indication of unstable gravitational forces that made three stars out of what was believed to be one fiery nucleus.

Young stars have been in the spotlight before, light-years away from the red carpet. Scientists have known what to expect since past observations showed that multiple-star systems tend to be varying distances away from companion stars. Stellar companions that are closer are assumed to have had a pretty uneventful emergence, with a smaller accretion disk whirling around the protostar, while those further away are gravity’s outcasts from a turbulent birth. What makes scientists especially excited about the new ALMA/VLA findings is that they back previous research on how multiple-star systems are a result of fragmentation, in both the discs swirling around the stars themselves and the colossal clouds of dust and gas that spawn them. L1448 illuminates how disk fragmentation can turn stars into multiple-star systems at a surprisingly early stage of development. They’re the kindergarten pageant queens of the universe.

"This whole system probably is less than 150,000 years old,” said University of Arizona astronomer Kaitlin Kratter, which is teenage compared to stars that could blow out billions of birthday candles. She indicated that it must be "the disk is unstable, and the most widely separated of the three protostars may have formed only in the past 10,000 to 20,000 years.” She and her colleagues are optimistic about more precocious star systems coming to light in the near future.

Get ready for many more candles on this cake.

(Via phys.org)