Hubble Telescope Catches a 'Stellar Thief' Star Stealing From a Nearby Supernova

Saturday, 28 April 2018 - 11:54AM
Space
Astronomy
Saturday, 28 April 2018 - 11:54AM
Hubble Telescope Catches a 'Stellar Thief' Star Stealing From a Nearby Supernova
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NASA
Never assume that a star is too big to steal. If you carelessly leave some spare hydrogen lying around, it'll snatch that right up in its gravity.

In this particular instance, the crime happened a long time ago, but astronomers only just cracked the cold case open using new evidence from the Hubble Space Telescope. While examining the remnants of a star named NGC 7424 which had gone supernova 17 years ago, the telescope picked up something unusual: another star conveniently close to the crime scene.

To break away from the silly crime metaphors, Hubble had picked up concrete evidence that a supernova had occurred in a double-star system or binary system - which scientists had predicted but never found proof of - and that the presence of a second star likely played a role in this supernova happening early. According to new research on the incident, this companion star was siphoning hydrogen from NCG 7424 and gradually destabilizing it. 

Going back to the silly crime metaphors, this wasn't just theft - it was murder.




NGC 7424 had large amounts of hydrogen in its "stellar envelope", a region of the star which transports materials from its core to its atmosphere. This companion star, due to its close proximity to NGC 7424, had been absorbing the star's hydrogen into its own gravity for millions of years prior to the supernova, causing the supernova to be known as a "stripped-envelope supernova" which detonates without any hydrogen. 

Even though light from the supernova only reached Earth 17 years ago, with the star being 40 million lightyears away inside the Grus constellation (which is known as the Crane), the initial blast was so bright that it concealed any other stars hiding around it. It was only recently that the glow had faded enough for Hubble to spot this second star, pointing to the supernova being just one half of a very bright binary sunset



According to Stuart Ryder, the lead author of the new research from the Australian Astronomical Observatory (AAO) in Sydney, most large stars tend to be in binary systems, meaning the famous Tattooine sunset from Star Wars is hardly a unique view throughout the universe (assuming there are solid planets to view it from).

Which is why it's so refreshing to find evidence of this behavior, as Ryder says in a press release from Hubble's website

Opening quote
"We know that the majority of massive stars are in binary pairs. Many of these binary pairs will interact and transfer gas from one star to the other when their orbits bring them close together."
Closing quote


The criminal star is likely to get away with it, sadly. But if you ever figure out how to fit a large, distant star inside of a courtroom, then you let NASA know.
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