It is not old enough. It is estimated that it would take trillions of years for a white dwarf to a black dwarf. The universe is only about 13.8 billion years old.

A red giant can have a radius of 50 million to 500 million kilometres.

by the big bang. the big bang happened and caused different gasses floating everywhere and combining to form different gasses like atom

Star clusters are collections of same-age stars that remain intact for billions of years. When plotted on a H-R diagram, a cutoff point of stars leaving the main sequence and massive stars further evolved are shown, confirming the theory of stellar evolution.

Helium burning is most durable stage in stellar evolution.

1. A nebula, an immense cloud of hydrogen gas and dust, condenses into smaller regions of matter.
2. On occasion, one of these regions collapses under the force of its own gravitational attraction, often triggered by an outside force, like a nearby supernova-an explosion of a star.
3. After the collapse of a cloud, atoms begin gravitating together to form a condensed center. The condensed center is a protostar. As gravity pulls in more gas and dust, pressure builds, causing the protostar core to heat up.
4. Clouds and matter begin to rotate around the protostar and flatten due to their rotation. They surround the protostar like a rotating disk.
5. The protostar continues to grow and its core continues to heat. When the core is hot enough, nuclear fusion begins. The start of nuclear fusion is technically the beginning of a star's life.
6. Eventually, when the nuclear energy runs out, the star dies. Depending on the size and mass of the star, it can go through many stages and die in different ways-one of those ways being a supernova.

It begins collapsing, which causes gravitational heating.

If the mass of the star is below a certain threshold the collapse stops, leaving a white dwarf.

If the mass of the star is above a certain threshold the gravitational heating makes the star hot enough to ignite helium fusion and the star begins making carbon. The now very hot stellar core makes the star expand to a red giant.