NASA data reveals strange radiological changes in the exploded ruins of dead stars

A set of supernovae behave strangely, more than a decade of data from NASA’s Chandra X-ray Observatory reveals. Instead of slowly fading away, as expected, the brightness of these exploded stars has varied significantly over the past 14 years.

Generally, when a a massive star explodes In a supernova, it leaves behind a cloud of superheated gas and debris. Over time, these stellar fireworks tend to fade, but Chandra observations of galaxy Messier 83 (M83) from 2000 to 2014 suggests that this is not always the case. Supernova remnants that researchers expected to have dampened X-ray emissions actually had a surprising variety in their X-ray brightness.

THE results were published in the Astrophysics Journal this month.

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M83 is about 15 million light years from Earth. Also called the Southern Pinwheel, this spiral galaxy is a hotbed of star formation. “We knew that individual X-ray sources could vary greatly,” Andrea Prestwich, an astronomer at the Catholic University of America and lead author of the study, said in a study. statement. “But discovering that so many supernova remnants behaved this way was a real surprise. There is something unusual going on in these objects. Identifying the cause remains a challenge, because the distance of M83 limits the details we can observe.”

At least one of the strange remains has an explanation: Debris from SN 1957D, a supernova first observed nearly 70 years ago, appears to be colliding with the matter around it, leading to increased X-ray emissions. But the cause of the other emissions changes is unclear.

One possible explanation, the researchers say, is a population of surviving stars that appear to have outlived their partner stars. If this is confirmed, then each X-ray source would have started as a pair of stars orbiting each other. In this scenario, when the more massive star exploded, its partner star did not explode. This would create what is called a high-mass X-ray binary, or HMXB, which could explain the variation in Chandra’s readings. HMXBs are not new, but they have not been historically linked to many supernova remnants.

Another potential cause of variations in X-ray emissions is that a black hole or neutron star, which sometimes remains after a star dies, attracts some of the material that was initially expelled outwards in a sort of cosmic recycling.

“This could be an example of cosmic recycling, where debris from the explosion falls back onto the very object created by the supernova,” said Roy Kilgard, co-author of the study and professor of astronomy at Wesleyan University, in the same statement. “And it is quite possible that both explanations are at play: different sources in our sample may have different origins.”

M83 isn’t the only galaxy where scientists have recently spotted these variable supernova remnants; a follow-up study also revealed them in Messier 51 (M51), or the Whirlpool galaxy.