现以太阳来说明红巨星(red giant)。英文简释：The star becomes a red giant,in which the hydrogen of the original star has expanded to become a huge ,red-coloured "envelope"of gas.The helium and carbon at the centre form a dense,compact core within the hydrogen "envelope".当一颗恒星度过它漫长的青壮年期——主序星(main sequence)阶段，步入老年期时，它将首先变为一颗红巨星。称它为“巨星”，
现以太阳来说明红巨星(red giant)。英文简释：The star becomes a red giant,in which the hydrogen of the original star has expanded to become a huge ,red-coloured "envelope"of gas.The helium and c
