Question

What is the initial stage of the Sun's evolution, characterized by the contraction of a giant molecular cloud and the formation of a protostar? Put the steps of the Sun's evolution in chronological order from 1 to 3

Answer 1

The initial stage of the Sun's evolution is the protostar stage, where a core in a molecular cloud collapses due to gravity. The Sun's evolution progresses through the main sequence phase to the red giant phase, with the H-R diagram illustrating these changes in temperature and luminosity.

Step-by-step explanation:

The initial stage of the Sun's evolution, characterized by the contraction of a giant molecular cloud and the formation of a protostar, is known as the protostar stage. The stages of the Sun's evolution in chronological order from 1 to 3 are:

1. Protostar stage
2. Main sequence stage
3. Red giant stage

During the protostar stage, the density of a core in a molecular cloud becomes high enough for gravity to cause the gas and dust to collapse, forming a protostar. Once the protostar has developed a strong stellar wind, material accumulation halts, with the early formation often marked by Herbig-Haro objects. The next phase is the main sequence, where the star stabilizes and gets energy from nuclear fusion. As the star exhausts its hydrogen fuel, it enters the red giant stage, which involves the expansion of the star's outer layers.

In an H-R (Hertzsprung-Russell) diagram, the evolution of a star such as the Sun is traced from the bottom right (protostar) moving leftward as it heats up and reaches peak luminosity on the main sequence, and then moves up and to the right as it cools and expands into a red giant.