Life of a StarBy Caitlin Shroyer and Angelleigh Gonzales

HOW ARE STARS FORMED? The star goes through many stages and they are: Small-medium stars Nebula Protostar Main Sequence Massive Main Sequence(High Mass Star) Red Giant Super Red Giant (High Mass Star) Supernova(High Mass Star) Neutron Star (High Mass Star ) Black Hole(High Mass Star) Planetary Nebula White Dwarf Black Dwarf

NEBULAIt’s made up of dust and dust particlesThe gravity begins to pull the particles in the

nebula together.

www. skyimagelab.com/m16-eagle-spire- wire.html

notes-formation of

stars

PROTOSTARA protostar is a dense area of gases in a nebula

that might become a star. If a protostar never gets larger than 1/10th mass

of the sun it becomes a brown dwarf.www. aspire.cosmic-ray.orgNotes-formation of stars

Brown DwarfBrown dwarfs never hot enough to start

fusion They shine dimly, but slowly cool off. The

Brown Dwarf is the 3rd stage of a star. www. Reorbit.comNote-formation of a star

Main SequenceThe temperature and pressure keep

increasing. Hydrogen begins to fuse together. The protostar officially becomes a star when

fusion begins. The star is now in the Main Sequence.The Main Sequence is similar to MassiveMain sequence but it’s larger. The Main Sequence is smaller. www. Crdlx5.yerpli.am/sun-pics/index.php?spgmGal=sunpics&spgmPic=6&spgmFilters=#pic Notes-formation of stars

Massive Main SequenceThe Massive Main Sequence stars are the larger type of

the building of a star. During the phases of a star it’s like the middle part of the making of a star.

www.asrtocu.unam.mx/massive_stars/Notes-formation of a star

Red Giant Because it has run out of fuel, the star begins to cool, and

contract. The outer layers of the star fall inwards under gravity, and as they fall they heat up. A shell surrounding the central core becomes hot enough to fuse protons into alphas. So the star gains a new source of energy. The core of the star is now hotter than it was during its normal life and this heat causes the outer parts of the star to swell. The star becomes a giant. The radiation from the fusing shell has grown weak by the time it reaches the surface of the star. Weak radiation is red, so the star becomes a red giant.

www. Historyoftheuniverse.com Motes-formation of a star

Red Supergiant A red supergiant is the bigger version of a red giant - so far no surprise. But

with these stars with more than 8 to 10 solar masses (the exact value is still uncertain) the production of energy doesn't stop at helium or carbon.A red supergiant is made of several layers. The outer hull of red glowing hydrogen and helium is inactive. Below this is a layer in which hydrogen is fusioned to helium. In the next layer helium is fusioned to carbon. So it goes on until in the core iron is made. The supergiant shines extremely bright, but only for a short time (still several hundred thousand to million years). In the end the phase in which the star fusions sulfur and silicon to iron only lasts a few days to weeks. From iron no more energy can be made. The core cools down and implodes. The following supernova (of type II) disrupts the star and leaves a tiny neutron star or a black hole behind.

www.hubblesite.org

Notes-formation of stars

Supernova A supernova is a final, gigantic explosion of

a supergiant star at the end of it’s life.A supernova lasts for weeks or so, but shines

as bright as a galaxy of 100 billion ordinary stars.

www. Oberlin.edu/physics/Astronomy/supernova/index.com www.familyhomesnetwork.com/facts/supernova.facts.html

Neutron StarSuper dense core of a star over after 2

supernova.

Black Hole

Planetary Nebula

White Dwarf

Black Dwarf