Stellar objects, commonly known as stars, are massive celestial bodies composed of hot gases, mainly hydrogen and helium. These luminous spheres generate energy through nuclear fusion, where atoms combine to form heavier elements, releasing vast amounts of light and heat in the process.
Stars are born within large molecular clouds of gas and dust, known as nebulae. The gravitational force causes these clouds to collapse, forming dense cores. As the core’s temperature and pressure increase, a protostar is born. It continues to grow as gas and dust from the surrounding cloud accrete onto its surface.
Once a protostar reaches a critical mass, the immense pressure at its core triggers nuclear fusion. This ignition releases an enormous amount of energy, turning the protostar into a true star. The energy created by the fusion reactions counterbalances the force of gravity, maintaining the star’s stable structure.
Stars exist in various sizes, ranging from small, faint red dwarfs to massive, hot blue giants. Their size influences their lifespan, with smaller stars living much longer than their larger counterparts. Eventually, stars exhaust their nuclear fuel, causing their cores to collapse or expand, leading to the formation of nebulae, supernovae, or white dwarfs, depending on their initial mass.
