In the current photosphere, the helium fraction is lessened, along with the metallicity is only eighty four% of what it was from the protostellar period (prior to nuclear fusion inside the Main begun). Later on, helium will go on to accumulate in the Main, and in about 5 billion yrs https://felixvzcgj.wikipublicity.com/5458085/5_simple_statements_about_sun_explained