A supernova caused by a collision with a deceased neighbor

Collisions with a very compact neighbor can cause not only stars but very healthy stars to burn out and eventually form supernovae.

When a star dies, it doesn’t happen without the necessary turbulence. A supernova is a phenomenon in which a star explodes in some sort of astronomical fireworks display, and glows tremendously. The most famous type of supernova is the primary collapse supernova. In doing so, the massive star — whose mass is more than ten times the mass of the Sun — runs out of fuel and its iron core collapses into a black hole or neutron star.

Research by Caltech astronomers suggests that there is another type of primary collapse supernova: one in which the star dies prematurely as a result of its collision with its already “dead” companion.

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Signal

In 2017, researchers detected a particularly bright pulse of radio waves in data from the Very Large Array (VLA) Radio Astronomy Observatory. The radio signal in question, VT 1210 + 4956, is the result of a supernova. It is believed to have been created by the interaction between matter thrown into space during the explosion and the gas cloud that shook a nearby star a few hundred years ago.

This, the researchers write in a professional journal ScienceTurns out it’s not the whole story. For more clues about the exact origin of this bright signal, astronomers turned to other data: X-rays. And yes: from the same source as VT 1210+4956, about 500 million light-years from Earth, the X-rays appear to have traveled to space years ago.

compressed neighbor

Astronomers believe that the star responsible for the supernova possesses a binary star: a companion that orbits around the same center of gravity. That neighboring star had previously died and orbited the star as a highly compressed black hole, or possibly a neutron star.

This dead neighbor’s cloud would have sucked material out of the star over the years. Part of the matter was thrown into space as a result of the intense spinning force of the black hole (or neutron star). There would have been a doughnut of gas around the pair.

fatal collision

Ultimately, the researchers believe, this “dance,” in which the dying star drags and pulls, would have ended in a cosmic collision, in which the star explodes in a supernova. The X-ray signal can be attributed to this. Years later, the material associated with this explosion would have reached a “gas cake,” resulting in a subsequent bright radio pulse.

It was suspected for some time that such a merger could lead to a supernova. However, it has not been observed like this before.

Resources: ScienceAnd California Institute of TechnologyAnd EurekAlert!

BILD: Chuck Carter/Caltech