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Astronomers say ‘obese’ neutron star contradicts black gap principle | Black holes

Astronomers say ‘obese’ neutron star contradicts black gap principle | Black holes

The “obese” of a neutron star has been noticed by astronomers who say the mysterious object is confounding astronomical theories.

A supermassive star was fashioned by the merger of two smaller neutron stars. Such collisions normally end in neutron stars so large that they virtually immediately collapse right into a black gap beneath the affect of their very own gravity. However current observations have proven that the monster star hovered in view for greater than a day earlier than disappearing from view.

“Such a large, long-lived neutron star just isn’t usually thought attainable,” mentioned Dr Nuria Jordana-Mitians, an astronomer on the College of Tub. “It stays a thriller why this one was so long-lived.”

The observations additionally increase questions concerning the supply of the extremely energetic bursts often called quick gamma-ray bursts (GRBs) that accompany merging neutron stars. These flares – probably the most energetic occasions within the universe for the reason that Huge Bang – are thought to originate from the poles of the newly fashioned black gap. However on this case, the noticed gamma-ray burst needed to come from the neutron star itself, which signifies a very totally different course of.

Neutron stars are the smallest, densest stars in existence, occupying the candy spot between bizarre stars and black holes. They’re about 12 miles extensive and so dense {that a} teaspoonful of the fabric would have a mass of 1 billion tons. They’ve a clean crust of pure neutrons, 10 billion instances stronger than metal.

“They’re such superb unique objects,” mentioned Professor Carol Mandell, an astronomer on the College of Tub and co-author of the examine. “We will not gather this materials and produce it again to our lab, so we are able to solely examine it after they’re doing one thing within the sky that we are able to observe.”

On this case, Mandell mentioned, one thing seems to have prevented the neutron star from “noticing how large it’s.” One risk is that the star was spinning so quick and with such big magnetic fields that its collapse was delayed — sort of like how water stays inside a tilted bucket if you happen to spin it quick sufficient.

“That is the primary direct view of a supermassive neutron star rotating in nature,” Mandel mentioned. “I assume we’ll discover extra.”

The sudden observations have been made by NASA’s Neil Gehrels Swift Orbiting Observatory, which detected the preliminary burst of gamma rays coming from a galaxy about 10.6 billion light-years away. The robotic observatory Liverpool Telescope, positioned within the Canary Islands, mechanically rotated to view the consequences of the merger. These observations revealed the hallmarks of a extremely magnetized, quickly rotating neutron star.

This means that the neutron star itself triggered the gamma-ray burst, somewhat than following its gravitational collapse. It’s nonetheless troublesome to establish the precise sequence of occasions.

“We have been excited to catch the very early optical mild from this quick gamma-ray burst — one thing that’s largely unattainable to do with out utilizing a robotic telescope,” Mandel mentioned. “Our discovery opens up new hope for upcoming surveys of the sky with telescopes such because the Rubin LSST Observatory, during which we are able to discover indicators from tons of of 1000’s of such long-lived neutron stars earlier than they collapse and turn out to be black holes.”

Stefano Covina, an astronomer on the Brera Astronomical Observatory in Milan who was not concerned within the examine, mentioned: “The group discovered proof for the existence of a metastable hypermassive neutron star, which is a very necessary discovering.”

He mentioned the work might present new insights into the inner construction of neutron stars, that are thought to have a core of unique matter, though the precise type this takes is unknown.

The findings are revealed in Astrophysical journal.


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