Its total mass mainly determines its evolution and eventual fate. A star shines for most of its active life due to the thermonuclear fusion of hydrogen into helium in its core. This process releases energy that traverses the star's interior and radiates into outer space.
A star’s gas provides its fuel, and its mass determines how rapidly it runs through its supply, with lower-mass stars burning longer, dimmer, and cooler than very massive stars.
Star, any massive self-luminous celestial body of gas that shines by radiation derived from its internal energy sources. This article describes the properties and evolution of individual stars.
A star that consumes hydrogen to form helium is called a "main-sequence" star for all the time it is a hydrogen-fusing object. When it uses up all its fuel, the core contracts because the outward radiation pressure is no longer enough to balance the gravitational force.
A star’s mass determines its temperature and luminosity, and how it will live and die. The more massive a star is, the hotter it burns, the faster it uses up its fuel, and the shorter its life is.
The amount of material in a star (its mass) is so huge that a nuclear reaction called nuclear fusion goes on inside it. This reaction changes hydrogen to helium and gives off heat.
Scientists call a star that is fusing hydrogen to helium in its core a main sequence star. Main sequence stars make up around 90% of the universe’s stellar population.
Star - Formation, Evolution, Lifecycle: Throughout the Milky Way Galaxy (and even near the Sun itself), astronomers have discovered stars that are well evolved or even approaching extinction, or both, as well as occasional stars that must be very young or still in the process of formation.