Astrophysics & Particle Physics-APPC 2026

Stellar Evolution is the study of how stars form, live, and die, governed by their mass, composition, and energy production. It explains the life cycle of stars, from their birth in molecular clouds to their ultimate fate as white dwarfs, neutron stars, or black holes.Stars form in dense molecular clouds when gravitational collapse causes gas and dust to coalesce, creating a protostar. As the core temperature rises, nuclear fusion begins, converting hydrogen into helium and releasing energy that stabilizes the star. This stage, known as the main sequence, constitutes the longest phase in a star’s life.The evolution of a star depends on its mass. Low-mass stars evolve into red giants, shedding their outer layers to form planetary nebulae and leaving behind white dwarfs.

High-mass stars expand into supergiants, undergoing more complex fusion processes to create heavier elements, eventually exploding as supernovae. These explosions can leave behind neutron stars or black holes, depending on the progenitor mass.Stellar nucleosynthesis, the process of element formation within stars, is a critical aspect of stellar evolution. It explains the origin of most chemical elements in the universe, enriching the interstellar medium when stars die. Observations of star clusters and galaxies allow astronomers to study stellar populations, ages, and chemical composition, providing insights into galactic evolution.Advanced models of stellar evolution incorporate hydrodynamics, radiative transfer, magnetic fields, and rotation to accurately describe stellar structure and lifecycle.

Observational techniques, such as spectroscopy and photometry, help verify these theoretical models and understand the physical properties of stars.By studying stellar evolution, scientists gain a comprehensive understanding of how stars influence their surroundings, contribute to cosmic chemical enrichment, and drive astrophysical phenomena. It connects stellar physics with galactic evolution and the broader universe, forming a cornerstone of modern astrophysics.