How do stars grow?

Stars grow within vast clouds of gas and dust called molecular clouds.

Stellar Nurseries: Molecular Clouds

Molecular clouds are the birthplace of stars. Here's a breakdown:

Size and Mass: These clouds are immense, ranging from 1,000 to 10 million times the mass of our Sun and can extend hundreds of light-years across.
Composition: They primarily consist of gas and dust, which serve as the raw materials for star formation.
Temperature: Molecular clouds are very cold, allowing the gas to clump together, creating areas of higher density.

Here is a simplified look at how stars develop within molecular clouds:

Clumping: Due to the cold temperatures within molecular clouds, gas and dust begin to clump together. This clumping creates dense pockets within the cloud.
Gravitational Collapse: Once these clumps reach a critical density, gravity takes over. The material begins to collapse inward, drawing more gas and dust towards the center.
Protostar Formation: As the material collapses, it heats up and forms a protostar, a dense, hot core. This protostar isn’t a star yet, but a star in development.
Nuclear Fusion: Once the core of the protostar becomes hot enough, nuclear fusion begins. This is where hydrogen atoms are fused into helium, releasing tremendous energy. When fusion begins, a star is born.
Main Sequence Star: The newly formed star stabilizes, with its outward pressure from fusion balancing the inward pull of gravity. The star then enters its main sequence phase.

Factor	Description
Molecular Clouds	Large, cold clouds of gas and dust which provide the raw materials for star formation.
Gravity	The force that pulls the gas and dust together, leading to collapse and the formation of a protostar.
Nuclear Fusion	The process in which the core of the star produces energy, converting the protostar into a true star.
Main Sequence	The stage when stars balance gravitational forces and the outward pressure from fusion.