How do molecular clouds become sites of new star formation?

Molecular clouds serve as the primary nurseries for new stars. Within these vast, cold, and opaque nebulae, star formation is triggered by the gravitational collapse of dense regions known as cloud cores.12

The process generally unfolds as follows:

• Gravitational Instability: While turbulence and magnetic fields typically support a cloud against its own gravity, specific dense clumps within the cloud eventually become unstable and begin to collapse.12
• Protostar Formation: As a core collapses, it flattens due to its rotation, forming a central condensation called a protostar surrounded by a rotating disk of gas and dust.12
• Accretion and Heating: The protostar grows by accumulating infalling material. As it contracts, gravitational energy is released, causing the internal temperature to rise.2
• Ignition: Once the core temperature reaches approximately ${10}^7$ K, hydrogen fusion ignites, marking the birth of a new star.2

Newly formed stars are often highly active, eventually blowing powerful winds that clear away the remaining gas and dust, effectively ending the accretion process.2