Question

Why do we clssify sun as a star

Answer 1

maybe because it is also a huge mass of gases like other stars

Answer 2

That's because 1)sun emits light of its own
2)It undergoes nuclear fission and fusion both 3)Hydrogen atoms break to form helium atoms,and this reaction emits a huge ,very huge indeed,amount of heat and light which we get on earth.
4)It is very large in size
5)Many planets and planetoids revolve around it .

Hope this will help u......