A star is formed by the gravitational collapse of interstellar gas and dust in a so-called molecular cloud. These clouds are huge accumulations of gas and dust in the vastness of space. When enough gas and dust have come together in a molecular cloud, gravity can begin to compress and heat the material.
The collapse increases the density and temperature of the gas inside the cloud. When the temperature is high enough, the hydrogen gas in the cloud’s core begins to fuse and a new star is born. This fusion of hydrogen into helium releases enormous amounts of energy, giving the star the energy it needs to shine and stabilize against gravity.
In its early stages, the emerging star is surrounded by an accretion disk in which remaining gas and dust particles collect. This disk can later lead to the formation of planets. Over its lifetime, the star converts its original supply of hydrogen fuel into heavier elements, releasing energy in the form of light and heat.
How does a star die?
The way a star dies depends on its original mass. Stars can end in different ways depending on whether they have more or less mass than the Sun.
Stars that are about the same mass as the Sun go through a phase at the end of their lives in which their core runs out of hydrogen fuel and fuses into helium. During this phase, the star slowly grows larger and becomes a red giant. Eventually, the star blows off its outer shells, leaving behind a compact core called a white dwarf.
Heavy stars, on the other hand, which are more than about eight times as heavy as the Sun, can end their lives in a much more dramatic way. These stars fuse heavier elements during their lives and reach the state of an iron core at the end of core burning. Iron is the element where fusion is no longer energetic enough to overcome the star’s gravity, causing the star’s core to collapse.
When the core collapses, the star explodes in a spectacular supernova explosion, releasing an enormous amount of energy and matter. In some cases the core can be compressed into an extremely dense neutron star, while in other cases a black hole can form.
Overall, it can be said that stars can end in different ways, depending on their original mass. The final stages of a star’s life cycle are often marked by spectacular events that release enormous amounts of energy and matter.