Stars form in large clouds of gas and dust called molecular clouds. Many other stars are visible to the naked eye at night Their immense distances from earth make them appear as fixed points of light The most prominent stars have been categorised into constellations and asterisms, and many of the brightest stars have proper names. This article describes the properties and evolution of individual stars Included in the discussion are the sizes, energetics, temperatures, masses, and chemical compositions of stars.
Stars are huge celestial bodies made mostly of hydrogen and helium that produce light and heat from the churning nuclear forges inside their cores. Stars are massive, luminous spheres of gas, mainly composed of hydrogen, with smaller amounts of helium and other elements The lifespan of a star varies widely, generally ranging from several million to several trillion years. A star is a massive, luminous sphere of plasma held together by gravity The nearest star to earth is the sun, which is the source of most of the energy on the planet. Stars are spherical balls of hot, ionized gas (plasma) held together by their own gravity
