questions about main sequence and massive stars?

[AnimePrinCEss0796]

what's the difference between the two, and the evidence that supports it? This isn't homework, I just don't understand it. Can you also tell me what the lifecylce of a star is? There are so many explanations, it's hard to make sense of it all. I'm in 8th grade btw.

[eelfins0249]

All stars have a main sequence phase; but the more massive a star is, the less time it spends on it. The main sequence is a phase of hydrostatic equalibrium in which the expansive heat from nuclear reactions in the core balance the gravitational force trying to contract it. The main sequence ends when the star runs out of nuclear fuel, then it collapses under gravity. Smaller stars just shrink into white dwarfs, and lose most of their outer atmospheres as a planetary nebula. Large stars collapse violently, the shockwave sending most of the star flying outward in a supernove explosion, while the core settles down as a neutron star or white dwarf.

[beernotcider]

Main sequence stars are in their mid-life term. The more massive a star is, the shorter it's time on the main sequence. A red dwarf, for instance, could possibly remain on the main seq. for the entire life of the Galaxy. TheSun, on the other hand, is about halfway through it's life. (About 5 billion years old.) A really massive star will use up it's hydrogen fuel so rapidly that it will stay on the main seq. for only a million years or less.

[AndyMan8840]

Main sequence is a term for stars as they enter into their mid-life stage. The same goes for the terms proto star (referring to stars yet to be born) and red giants (stars that have passed main sequence and are moving towards their end).Massive stars, like red giants, blue giants, and red hypergiants, are all phases of stars. It is normally the phase after the main sequence of a star. What happens inside the star is the key difference besides the obvious size change. To put it simply, Main Sequence stars fuse hydrogen atoms together to make helium. Massive stars then move off of that. Massive stars fuse elements to make carbon and oxygen. The lifecycle of a star is basically the life of a star. It's the phases a star goes through. For instance, a star is first born (after enough matieral is collected for it to begin fusing hydrogen), then it goes into its main sequence stage, then soon after, goes into its 'massive' stage. Then at the end of all this, the star dies. Just like how a human is born, becomes a child, then a teenager, then an adult, then a senior citizen, and then dies.Hopefully this helps.