Stellar Birth

Stars are born within cold, dense molecular clouds—regions rich in hydrogen molecules (H₂), helium, and trace amounts of elements like carbon, oxygen, and nitrogen.

Gravitational instabilities, often triggered by shockwaves from nearby supernovae or galactic collisions, cause parts of these clouds to collapse.

As the gas contracts, gravitational energy converts to thermal energy, heating the core.

Chemical processes within the collapsing protostar include molecular hydrogen dissociation and ionization of atoms, which regulate temperature and pressure.

When core temperatures exceed about 10 million Kelvin, nuclear fusion of hydrogen into helium begins, marking the birth of a main-sequence star and releasing vast amounts of energy that counterbalance further collapse.