Question

What are the stages in the life cycle of a small star?

Answer 1

There are basically seven stages of the life cycle of small and medium sized stars. Massive stars i.e. the stars having huge masses, then the average star e.g. sun exhibit additional phases as well. All the stars irrespective of their size go through the above seven stages which start as a gas cloud and end as a star remnant.

Complete step-by-step solution:
Stars approximately the size of the sun are considered to be small stars. But these are not as small as red dwarves which are half the size of the sun.
The first stage involves the formation of a star from a giant gas cloud. The temperature is low enough for the synthesis of the molecules. The second stage involves the formation of the heat energy when energy when the molecules formed run into each other. This results in the formation of a warm clump called the Protostar. The next phase is called the Tauri-phase which gets initiated as the material stops falling into the Protostar and releases a tremendous amount of energy. This phase is followed by the main sequence in which the temperature in the core is high enough for the initiation of fusion reaction and ultimately, the protons fuse to form helium. As soon as the hydrogen from the core gets exhausted, there is no enough hydrogen for the formation of helium which releases energy. Without the reactions occurring at the core, the star contracts inward through gravity causing it to expand. This phase is usually known as the Red giant as the stars appear dark red. The next phase is the fusion of heavier elements wherein the atoms of the lower atomic number fuse to give the atoms of the higher atomic number. In case of small stars like the sun, they contract to form white dwarfs.

Note: It is to be noted that the stars are more massive than that of the sun, whose material gets blasted into space and its core implodes into a neutron star. Stars tinier than the sun don’t have enough to burn with anything during the main sequence but give a red glow. The primary determinant of a star's characteristics is the amount of stardust involved in its formation.