Stellar nucleosynthesis in stars or their remnants creates almost all naturally occurring chemical elements heavier than lithium. At the end of a star's lifetime, its core becomes a stellar remnant: a white dwarf, a neutron star, or-if it is sufficiently massive-a black hole. This process releases energy that traverses the star's interior and radiates into outer space. A star shines for most of its active life due to the thermonuclear fusion of hydrogen into helium in its core. Its total mass is the main factor determining its evolution and eventual fate. Only about 4,000 of these stars are visible to the naked eye, all within the Milky Way galaxy.Ī star's life begins with the gravitational collapse of a gaseous nebula of material composed primarily of hydrogen, along with helium and trace amounts of heavier elements. The observable universe contains an estimated 10 22 to 10 24 stars.

Astronomers have assembled star catalogues that identify the known stars and provide standardized stellar designations. The most prominent stars have been categorised into constellations and asterisms, and many of the brightest stars have proper names. Many other stars are visible to the naked eye at night, but their immense distances from Earth make them appear as fixed points of light. A star-forming region in the Large Magellanic CloudĪ star is an astronomical object comprising a luminous spheroid of plasma held together by its gravity.

Express burn disk