Death of a Star

What happens when a star dies? Does every star form a black hole?

To understand in depth, let's categorize the stars as:

• Stars like the Sun.

• Stars more massive than Sun.

Stars like the Sun

When the core runs out of hydrogen fuel, it will contract under the weight of gravity and heat up. This heats the upper layers, causing them to expand, increasing the radius & it will become a red giant.

At some point after this, the core will become hot enough to cause the helium to fuse into carbon. The helium fuel runs out & the core expands and cools. The upper layers will expand and eject material that will collect around the dying star to form a planetary nebula.

Finally, the core will cool into a white dwarf and then eventually into a black dwarf.

This entire process will take a few billion years.

Stars more massive than Sun

When the core runs out of hydrogen, these stars fuse helium into carbon, just like as in Stars like Sun.

However, after the helium is gone, their mass is enough to fuse carbon into heavier elements such as oxygen, neon, sulfur and iron.

Once the core has turned to iron, it can not burn any longer. The star collapses by its own gravity and the iron core heats up. The core becomes so tightly packed that protons and electrons merge to form neutrons.

In less than a second, the iron core shrinks to a neutron core with a radius of about 10 kilometers!

The outer layers of the star fall inward on the neutron core, hence, crushing it further. The core of star heats to billions of degrees and explodes, also known as supernova, thereby releasing large amounts of energy and material into space.

The remains of the core can form a neutron star or a black hole depending upon the mass of the original star.

---

Hence, there is one thing for sure, a star's death isn't the end of astronomical magnificence, instead, it is the birth of far more phenomenons we are yet to explore!