Question 1:

What is a protostar?

Explanation: A protostar is a young, forming star that is still in the process of accreting matter from its surrounding molecular cloud. It represents an early stage in stellar evolution before the star reaches a stable phase of fusion.

Question 2:

What forces are involved in the collapse of a molecular cloud to form a protostar?

Explanation: The collapse of a molecular cloud to form a protostar is primarily driven by gravitational forces. However, magnetic forces and pressure forces also play a role in regulating the collapse and determining the properties of the resulting protostar.

Question 3:

Which of the following is a characteristic of a protostar?

Explanation: A protostar is characterized by a surrounding accretion disk of gas and dust, which is a result of the ongoing process of material accretion onto the forming star. It does not possess stable nuclear fusion, well-defined stellar structure, or high luminosity like a main-sequence star.

Question 4:

At what point in stellar evolution does a protostar become a main-sequence star?

Explanation: A protostar becomes a main-sequence star when it reaches a stable phase of nuclear fusion in its core. This occurs when the temperature and pressure at the core are sufficient to initiate and sustain hydrogen fusion reactions.

Question 5:

What is the approximate mass range of protostars?

Explanation: The approximate mass range of protostars is from 0.01 to 1 solar mass. This range includes a significant portion of the stellar population and encompasses stars of various sizes and spectral types.