 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

Thanks For Watching