Hubble Spots ‘Stellar Thief’ Star Stealing Hydrogen From Neighboring Supernova
This amazing discovery is the first solid proof of a binary star system, NASA reveals.
NASA’s Hubble Space Telescope has detected a space crime, Outer Places reports. The telescope caught a glimpse of a “stellar thief,” a star that had been siphoning hydrogen from a nearby supernova, quite possibly leading to its neighbor’s extinction.
NASA provides the whole back story in a recent news release, explaining that the supernova, called SN 2001ig, was first sighted 17 years ago, when the light from its explosion eventually reached Earth. It’s swindling companion, however, was only recently observed, once the glare from the explosion started fading away and exposed a suspect presence near the dying star.
This cosmic murder mystery has a deep significance for the astronomers who uncovered it. This is the first time anyone has found actual proof that some massive stars, just like the one that was killed off in the supernova, can occur in binary star systems, where they coexist next to a companion star.
This first-ever documented binary star system was discovered by Hubble in “a galaxy far, far away,” lying at a distance of 40 million light-years from Earth, in the Grus constellation, also known as the Crane. The galaxy’s name is NGC 7424.
The Hubble photo that tied it all together “is the most compelling evidence that some supernovas originate in double-star systems,” NASA revealed in the news release.
The fortuitous discovery is also detailed in study published last month in the Astrophysical Journal.
“We know that the majority of massive stars are in binary pairs,” said lead study author Stuart Ryder, from the Australian Astronomical Observatory (AAO) in Sydney, Australia.
“Many of these binary pairs will interact and transfer gas from one star to the other when their orbits bring them close together,” he explained in the news release.
This was also the case with SN 2001ig and its stellar companion. SN 2001ig is a rare type of supernova, categorized as a Type IIb stripped-envelope supernova, which means that most of the hydrogen in is “stellar envelope” — the region of the star which transports materials from its core to its atmosphere — had already been depleted before the explosion.
The reason was none other than its thieving companion, which had been stealing hydrogen from SN 2001ig for millions of years, long before its unsuspecting victim went supernova.
With its neighbor constantly mooching off hydrogen, SN 2001ig eventually became unstable and started “to episodically blow off a cocoon and shells of hydrogen gas before the catastrophe,” states the NASA news release.
Similar occurrences are common in the universe, since “the sheer number of stripped-envelope supernovas is greater than predicted,” says study co-author Ori Fox of the Space Telescope Science Institute in Baltimore.
But Hubble was the first to ever capture evidence that binary star systems, long-time predicted, really exist.
“We were finally able to catch the stellar thief, confirming our suspicions that one had to be there,” said study co-author Alex Filippenko of the University of California, Berkeley, who was the first to discover Type IIb stripped-envelope supernovae in 1987.
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