Scientists Have Spotted A 'Cannibal Vampire Star' Escaping The Milky Way Galaxy

Thursday, 08 November 2018 - 1:17PM
Astronomy
Space
Thursday, 08 November 2018 - 1:17PM
Scientists Have Spotted A 'Cannibal Vampire Star' Escaping The Milky Way Galaxy
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NASA & the Hubble Heritage Team STScI/AURA Acknowledgment: D. Garnett University of Arizona
If there are galactic archaeologists, what about stellar homicide detectives? Scientists recently spotted a star called CPD 64°2731 zooming away from the Milky Way after absorbing its binary companion, and at least one commentator has characterized it as CPD 64°2731's attempt at fleeing the scene of the crime after murdering its partner. Putting aside the criminal dressings, it's a fascinating case of a "runaway" star, one that has de-aged itself as it heads out into the cosmos alone.

CPD 64°2731 (which we'll shorten to CPD 64 for brevity) is about forty times the mass of our Sun, but it's spinning much, much faster: while our Sun spins at a rate of about 2 km/second, CPD 64 is spinning at about 300 km/second. It's also traveling at an incredibly high speed – roughly 160 km/second.

These extreme speeds are the result of an impossible scenario: while forming in a gas cloud that gave birth to many other stars, CPD 64 formed close enough to another star to capture it (creating a binary system), then crossed paths with a third star in just the right way to get slingshotted out of the Milky Way (along with its partner) by the gravitational interaction. This explains its "runaway" status, as well as its strange position: about 2,000 light-years above the galactic disk.

From there, CPD 64 and its companion apparently grew closer and closer until the smaller star was consumed, which replenished CPD 64's fuel supply and effectively de-aged it. It also picked up much of its companion's angular momentum, which explains its extreme rotation speed. To top it all off, the merger created a horseshoe-shaped nebula, which still surrounds CPD 64. 

Stellar cannibalism is one way for a star to extend its lifespan, but there's another, even more dramatic way: passing close to a black hole.

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