Group B Stars


Stars form when clumps of interstellar gas and dust collapse in on themselves and drive up internal temperatures and pressures. At a critical stage, nuclear fusion reactions begin and release vast amounts of energy.

Atoms of a star's main fuel, hydrogen, fuse together in the core to form helium. A sequence of fusion reactions at different stages of a massive star's life and eventual supernova death produces all the natural elements.

As successive generations of stars have burned out and exploded as supernovae, the elements have been spread around the Universe to form planets and all living things

A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth.

Other stars are visible from Earth during the night

Binary and multi-star systems consist of two or more stars that are gravitationally bound, and generally move around each other in stable orbits.


Stars are really hard to see, because of how small they actually are.. and you are really lucky if you see a shooting star

Some stars have always stood out from the rest. Their brightness is a factor of how much energy they put out, which is called their luminosity, and also how far away from Earth they are.
Stars in the heavens may also appear to be different colors because their temperatures are not all the same. Hot stars are white or blue, whereas cooler stars appear to have orange or red hues
Stars may occur in many sizes, which are classified in a range from dwarfs to supergiants. Supergiants may have radii a thousand times larger than that of our own sun.

Young stars at this stage are called protostars. As they develop they accumulate mass from the clouds around them and grow into what are known as main sequence stars. Main sequence stars like our own sun exist in a state of nuclear fusion during which they will emit energy for billions of years by converting hydrogen to helium
Stars evolve over billions of years. When their main sequence phase ends they pass through other states of existence according to their size and other characteristics. The larger a star's mass, the shorter its lifespan will be.
As stars move toward the end of their lives much of their hydrogen has been converted to helium. Helium sinks to the star's core and raises the star's temperature—causing its outer shell to expand. These large, swelling stars are known as red giants
The red giant phase is actually a prelude to a star shedding its outer layers and becoming a small, dense body called a white dwarf. White dwarfs cool for billions of years, until they eventually go dark and produce no energy. At this point, which scientists have yet to observe, such stars become known as black dwarfs.

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