Astronomers have found dramatic evidence that a black hole or neutron star spiraled its way into the core of a companion star and caused that companion to explode as a supernova. The astronomers were tipped off by data from the Very Large Array Sky Survey (VLASS), a multi-year project using the National Science Foundation’s Karl G. Jansky Very Large Array (VLA).
“Theorists had predicted that this could happen, but this is the first time we’ve actually seen such an event,” said Dillon Dong, a graduate student at Caltech and lead author on a paper reporting the discovery in the journal Science.
The first clue came when the scientists examined images from VLASS, which began observations in 2017, and found an object brightly emitting radio waves but which had not appeared in an earlier VLA sky survey, called Faint Images of the Radio Sky at Twenty centimeters (FIRST). They made subsequent observations of the object, designated VT 1210+4956, using the VLA and the Keck telescope in Hawaii. They determined that the bright radio emission was coming from the outskirts of a dwarf, star-forming galaxy some 480 million light-years from Earth. They later found that an instrument aboard the International Space Station had detected a burst of X-rays coming from the object in 2014.
Scientists think they may have found a type of supernova never before seen.
Why it matters: Typically, massive stars explode as supernovas when they run out of fuel, but researchers have been on the lookout for other kinds of stellar explosions that might help them better understand the strangeness of our universe.
What they found: A new study in the journal Science used data from the Very Large Array Sky Survey to figure out that a massive star’s explosion was likely triggered by a black hole or neutron star companion spiraling in and colliding with it.
- This marks the first time such a supernova has been spotted.
The big picture: Scientists know these types of star systems exist because of previous observations.
- These types of systems can usually involve the black hole or neutron star orbiting its companion star for millions or billions of years. (When they collide, they can create gravitational waves.)
- But in this case, the star and black hole or neutron star collided very quickly, creating a huge blast of radio waves that was seen by the VLA Sky Survey.
- “During this process you find yourself pulled in different directions by different explanations, and you simply let nature tell you what’s out there,” Dillon Dong, of Caltech, one of the authors of the new study, said in a statement.
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