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hydrogen fusion, interstellar dust, helium, nuclear fuels, supernovas

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Supergiant (star), extremely large, luminous star that can be seen from vast distances across space. Supergiants are stars that have evolved through several stages, converting the nuclear fuels in their cores to successively heavier elements at each stage. They often explode as supernovas when the nuclear fuels in their cores are exhausted.

Supergiants form in the same way that ordinary stars form—a cloud of hydrogen gas and interstellar dust compresses under the gravitational attraction of its matter for itself until the temperature at the center of the cloud is hot enough to fuse hydrogen to form helium. The central region where hydrogen fusion occurs is called the core. After hydrogen fusion occurs in a new star, electromagnetic radiation is released from the core. The radiation creates an outward pressure that balances the gravitational force, and the cloud eventually stabilizes as a main-sequence star—a star in the first and longest phase of its luminous existence.

The primary difference between a star destined to become a supergiant and a more typical star is its mass. Astronomers estimate that a star must be at least six to ten times more massive than the earth’s sun in order to have a core massive enough to make the star a supergiant. The additional mass leads to stronger gravitational forces that create the temperature and pressure conditions in the core needed to induce the fusion of heavy elements late in the life of the star. The additional mass also causes higher core temperatures in the star’s early phases and results in more rapid nuclear reactions than smaller stars. Astrophysicists estimate that the rate of fusion in a star is roughly proportional to the fourth power of its mass. Thus, a star with a mass of ten times the earth’s sun consumes hydrogen about 104 (10,000) times faster than the sun. Such a star will consume the hydrogen in its core within a few million years, whereas a star of the sun’s mass will last a thousand times longer.

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hydrogen fusion, interstellar dust, helium, nuclear fuels, supernovas, gravitational attraction, gravitational force, Supergiants, supergiant, electromagnetic radiation, sun, hydrogen, temperature, central region, cores, new star, earth, stages, matter, core, space, power, times, years, life, results, way, center, order

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