In a typical core-collapse supernova
, the inner collapse occurs so quickly that infalling layers of stellar material rebound off the core, driving a shock wave that sends much of the star flying outward.
To address this conundrum, researchers including Caltech astrophysicist Brian Grefenstette pointed NASA's Nuclear Spectroscopic Telescope Array at Cassiopeia A (below), the remnant of a nearby core-collapse supernova
whose light first reached Earth about 350 years ago.
These two grains are thought to have come instead from a core-collapse supernova
, a massive star that exploded at the end of its life.
Scientists initially suspected that RCW 86 was the result of a core-collapse supernova
, the most powerful type of stellar blast.
Washington, March 27 ( ANI ): Supernovae were always thought to occur in two main "flavors" - a core-collapse supernova
that is the explosion of a star about 10 to 100 times as massive as our Sun and a Type Ia supernova, which is the complete disruption of a tiny white dwarf.
Other features of the remnant, however, especially its dense shell of gas and dust, indicate that it came from a core-collapse supernova
That the blast repeats "tells you without a doubt that this is not a cataclysmic event like a core-collapse supernova
or a neutron star-neutron star merger, because that kind of event destroys the object," says coauthor Jason Hessels (Netherlands Institute for Radio Astronomy).
According to textbooks, a typical core-collapse supernova
goes something like this: Massive stars swell into red supergiants, then, with increasing desperation, they fuse successively heavier elements--helium, carbon, oxygen, neon, silicon--in an attempt to stave off gravity's fatal embrace.
Only at that point does it develop a large iron core and ultimately explodes as a core-collapse supernova
Several features indicate that 1987A is a core-collapse supernova
, in which gravity crunches a massive star's core down to a sphere only 20 kilometers in diameter.
If the blast that produced Cas A came from a core-collapse supernova
, as astronomers suspect based on the nature of its remnant, it's a mystery why it wasn't bright enough to be noticed.
Such a star rotates too slowly to form relativistic jets, so it dies as a normal core-collapse supernova
without a GRB.