A star is a ball of hydrogen, helium and enough mass that can bear nuclear fusion at its core Stars are most often seen at night in a clear sky Stars are NOT in our solar system What Is a Star??????
When a star is born it is born in a huge cloud of gas and dust particles known as a nebula Nebulas can be 21 light-years across that is 125 trillion miles Parts of the nebula begin to shrink under its own gravity and forms into a protostar Birth Of A Star
Life Of a Star! For Nuclear fusion to take place huge amounts of pressure and heat are needed. When the pressure crushes elements together it creates more massive elements and energy. Hydrogen is the first to be fused from a star because it is the easiest to fuse. To form one nucleus of helium four hydrogen nuclei have to fuse together. By-products of this is the production of two positrons, two neutrinos, and the release of energy. This hydrogen burning process is known as the main sequence. Stars spend 90% of their life on this process.
Red Giants A Red Giant is a red star that has become bigger and brighter in the last stages of its life. The star is red because it is cooler than in the main sequence stage and it is giant because its outer shell has grown outward The amount of mass a star has will determine which life cycle path will be taken Low mass stars have a diameter of 60 million miles as a red giant
Low mass stars Low Mass Stars follow the average star path. The Average star follows this list Red Giant, planetary Nebula, White Dwarf, then Black Dwarf
Planetary Nebula A Planetary Nebula is a shell of gas thrown off by a star similar to our own in late development. A planetary nebula is created when a star blows off its outer layers after it has run out of fuel to burn. These outer layers of gas expand into space, forming a nebula which is often the shape of a ring or bubble. They are called Planetary Nebulas because they are round like planets
White Dwarf A white dwarf is what stars become after they have exhausted their nuclear fuel. Near the end of its nuclear burning stage, a white dwarf star lets go of most of its outer material, creating a Planetary Nebula.
Black Dwarf A black dwarf is a white dwarf that has cooled down enough to where it no longer ‘counts’ as a star.
Massive Star Cycle A massive star is a star that has high mass They follow this path Red Supergiant, Supernova, Neutron Star, or Black hole
Red Supergiant A Red Supergiant is a star that is similar in nature but more massive than a Red Giant. Red Supergiants belong to Luminosity Class I The supergiant phase is for about a few hundred years to 1 million years before becoming a supernova
Supernova A supernova is an exploding star that can become billions of times as bright as the sun before slowly fading from veiw At the maximum brightness, the exploded star may outshine the entire galaxy. The explosion throws a large cloud of dust and gas into space. The mass of the excess material may exceed 10 times the mass of the sun. Most supernovas can reach maximum brightness in a few days after occurring and shining strongly for several weeks
Neutron Star A Neutron Star is a star that has ran out of fuel and collapsed Neutron stars are very hot and are supported against further collapse
Black Hole A black hole is formed when a star of high mass undergoes gravitational collapse, with most or all of its mass compressed into a small area of space Black holes do not suck up the matter in space