Star-smash supernova? New type of stellar explosion possibly seen
By Charles Q. Choi about 12 hours ago
'A merger-triggered supernova, I think, is just scratching the surface of what's possible.'
This artist’s illustration shows a compact object (a black hole or neutron star) at the core of its massive stellar companion. Rapid accretion onto the compact object has caused it to form an accretion disk and launch a pair of jets at nearly the speed of light. Those jets have tunneled through the star, which is about to explode in a supernova due to the enormous amount of energy released. In the next few years, the exploded stellar material will plow its way through a dense torus of stellar material ejected by the compact object during its previous centuries of inspiral toward the core, creating a luminous radio afterglow. (Image credit: Chuck Carter)
Astronomers have uncovered evidence of explosions triggered by dead stars ramming into live stars, possible proof of a new type of supernova, a new study finds.
Supernovas are gigantic explosions that can occur when stars die. These outbursts can briefly outshine all of the other suns in these stars' galaxies, making them visible from halfway across the cosmos.
For decades, researchers have known of two main supernova types. Large stars more than 10 times the sun's mass collapse in their centers when their cores burn all their fuel, causing the outer layers to explode and leaving behind a stellar remnant such as a neutron star or black hole. In contrast, stars less than eight times the sun's mass burn out over time, leaving behind a dense core known as a white dwarf, and these remnants can pull fuel onto themselves off companion stars until they detonate in a thermonuclear explosion.
However, scientists have suggested other kinds of supernovas may exist. For example, most stars more than eight solar masses are born in close orbits to companion stars. The heavier members of these pairs may die first as supernovas, leaving behind a neutron star or black hole that can theoretically spiral toward its partner and collide, triggering a supernova.
More:
https://www.space.com/new-type-supernova-star-merger