Aug 20, 2019 | Updated: 11:45 AM EDT

Star Sets Galactic Speed Record

Mar 10, 2015 02:34 PM EDT


While most stars hang out in the Milky Way for millions or even billions of years in orbit of the center of the galaxy, the star known as US 708 is marching to its own drum.

US 708 is moving at what is known as "hypervelocity" and finding its own path at a speed of about 1,200 kilometers per second or 2.7 million miles per hour.  At that speed the star will be able to escape the gravity of the Milky Way and become a universal traveler.

"At that speed you could travel from Earth to the moon in five minutes," coauthor of the new study and researcher with the University of Hawaii, Eugene Magnier says. US 708 will leave the Milky Way in about 25 million years, eventually making its way to intergalactic space and cooling down to form a white dwarf star.

A team of researchers using the Keck and Pan-STARRS1 telescopes on Hawaii's Mauna Kea combined new observations with old to determine that it sets the new speed record in the Milky Way. 

Scientists have learned that the origin story of this particular star is different from all other hypervelocity stars studied in the past.  An analysis of the trajectory, for example, reveals that this star did not originate from the center of the galaxy.  In addition, the star rotates rapidly and is a compact helium star further differing it from other hypervelocity stars. 

"US 708 does not come from the galactic center. We don't know any other supermassive black hole in our galaxy. One needs one of those. A smaller, stellar-mass black hole formed by the collapse of a massive star can't do the job," Stephan Geier from the European Southern Observatory, who was involved in the study, says.

Scientists believe that the star could have once been a part of a binary system in which it had close interaction with a massive white dwarf star that pulled in its helium resulting in a supernova explosion that sent the star into the galaxy like a large piece of galactic shrapnel. 

Scientists hope that this discovery could shed some light on how this type of supernova, known as a Type Ia, occurs.

"We have made an important step forward in understanding (type I supernova) explosions," the researchers say. "Despite the fact that those bright events are used as standard candles to measure the expansion (and acceleration) of the universe, their progenitors are still unknown."

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