The Life of a Star
Types of Star
The stars that we see above us every night are all different size, brightness and colour. This is because there are several diffenert types of star. The four main types that you have to know for GCSE are Dwarfs, Main Sequence stars, Giants and Super Giants.
This is the Hertzsprung Russel or HR diagram. It shows all the various tyoes of stars in relation to each other based on their temperature and luminosity/brightness. This shows us the properties of each different type of star.
The Dwarfs are the smallest class of sun. (http://en.wikipedia.org/wiki/White_dwarf) They are the smallest main-stream star class we know about. However, they are also amoung the hottest stars we know. They are small and as a result the pressure and gravity laws dictate that they should be hot, as they are.
Main Sequence stars are the most common class of star. (http://en.wikipedia.org/wiki/Main_sequence_star) They span the entire range of both temperature and size. Our own sun (Sol) is a main sequence star.
Giants are the next biggest class of star. (http://en.wikipedia.org/wiki/Giant_star\) They are very big, far larger than our sun and are bright but cool. Although this is seems to be a contradiction in terms it is possible, I just don't know how! Go look it up.
Super Giants ar the largest class of star that we are aware of. (http://en.wikipedia.org/wiki/Supergiant_star) They are huge (between 10-70) solar masses. (Thats big!). They are extremely bright but not very hot, this is because they are so massive it takes so much energy to heat up such a large area.
Main Sequence Stars
OCR think these are the most important class of star and as such there is a whole section devoted to them you need to learn. Despite having powerull telescopes and probes, the sun is around 5500K hot which melts most things, actually... everything, so we cannot tell exactly what is in a star. howevr, there are some clues. the first thing we know is that there an area of around a million degrees for fusion to take place. The…