Question

What causes a massive star to explode as a supernova?

Answer 1

Really massive star may result in a supernova if there is a change in its core.

Explanation:

The change may occur in two ways, classified as type 1 and type 2, both are explained below-

1. Type I supernovae lack a hydrogen signature in their light spectra. It occurs in binary star systems. In this one of the stars, generally a carbon-oxygen white dwarf, steals matter from its partner star and thus over time, the white dwarf accumulates too much matter. The star could no longer tolerate the excessive matter, thus resulting in a supernova(explosion of a massive star).

This is further classified into two sub-divisions,i.e. Type 1a and 1b.

In Type Ia all the stars blaze with equal brightness at their peaks.
But Type Ib and Ic are a bit similar to type 2 as their core collapse just as type 2, but it have lost most of their outer hydrogen envelopes.

1. Type II occurs when its the time for the star to die or it becomes a white dwarf. In this time the star lacks nuclear fuel i.e. hydrogen and helium in its core, enabling some of its mass to flow to the core. Over time, the core becomes so heavy that it cannot withstand its own gravitational force making the core to collapse, this results in the giant explosion of a star known as supernova.

It is also further classified on the basis of the light curve. They are type II-L and II-P.

The light of Type II-L supernovas declines steadily after the explosion. The light of the Type II-P stays steady for a time before diminishing.