Our Sun is classified as a main-sequence star, specifically a G-type star. This classification is based on its mass, temperature, and luminosity, placing it in the middle range of the stellar classification scale. The Sun generates energy through nuclear fusion in its core, where hydrogen is converted into helium, releasing immense amounts of energy that power the solar system. As a main-sequence star, the Sun is stable and has been in this phase for approximately 4.6 billion years, with an estimated remaining lifespan of about 5 billion years before evolving into a red giant.