Stars P7 ocr GCSE Physics 21st century

In the middle you have a core which is where all of the nuclear fusion which turns hydrogen in to helium happens this is the really hot part of a star ( in a red giant - a star can prodcue heavier elements such as carbon nitrogen and oxygen - becuase stars make all the elemnts we could be considered to be star dust ) the elements that a star contains can be seen from emission and absorbsion specta so make sure you know how to interpret these 

around the core you have the convective zone which allows energy to be transfered to the surface of a star on convection currents like the ones that move the earth tectonic plates

and finally  you have the photosphere which is the part of the star that releases/ radiates  all of the energy into space from the star

these are stars which later in size over a given period of time for example a week and this varying size of star will cause it to  have  a higher interistic brightness( a stars real brightness) as this is effected by the size and temperature of a star

we can work out the distance to a star if we know the actual brightness as well as how bright it appears and this is what hubble did to solve the curtis shapely debate as the stars where all in the same galaxy he figured that the distance was about the same to these stars and used other data to find there periods and intristic brightness and find that they were so far away they had to be in a different galaxy 

 for a small star- nebula - average star- red giant - white dwarf- black drawf after cooling

for a big star - nebula - big star - super red giant which has an iron core becuase it is so hot it can produce very heavy elements becuase the heat and pressure allows the elements to cover come the electrostatic attraction  and allows themm to fuse - supernova- the star throws its outer layers off - neutron star or black hole depending on the size of a star