Can the amount of mass of a supernova star force the expelled material to return to the origin of the explosion?Like in the case when a rocket lounched from Earth has not suficient starting velocity to become completly free from forced returning to Earth caused by Earth's gravity?


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A supernova releases a lot of energy, much of it in the kinetic energy of the ejected matter. However, if the supernova leaves a remnant (a neutron star or a black hole) there is always some fallback of matter onto the remnant. This can be enough to convert a neutron star remnant into a black hole. From Wikipedia:

Some material from the outer envelope falls back onto the neutron star, and, for cores beyond about 8 M☉, there is sufficient fallback to form a black hole. This fallback will reduce the kinetic energy created and the mass of expelled radioactive material, but in some situations, it may also generate relativistic jets that result in a gamma-ray burst or an exceptionally luminous supernova.

Not all supernovae leave a remnant. Eg, low metallicity stars with mass in the range of around 140 to 250 solar masses collapse due to pair instability. These stars are so hot that the thermal photons are gamma rays with enough energy to create electron + positron pairs when they interact with the electric field of a nucleus. That is, thermal energy in the core gets diverted into creating matter & antimatter. This reduces the core pressure, so the core collapses leading to further pair production in a runaway process which is so intense that it blows the star completely apart, leaving no remnant.

On the other extreme, core collapse can occur in a star that doesn't have quite enough mass to produce a supernova explosion, so virtually all the matter falls back. This is referred to as a failed supernova.


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