Helium star transform into a red giant after losing its hydrogen envelope in the future. Helium star A helium star or helium strong star is a class O or B star (blue), which has extraordinarily strong helium lines and weaker than normal hydrogen lines, indicating strong stellar winds and a mass loss of the outer envelope. "Extreme helium stars" (EHe) entirely lack hydrogen in their spectra. Previously, a "helium star" was a synonym for a B class star, but this usage is considered obsolete. A "helium star" is also a term for a hypothetical star that could occur if two helium white
Giant star This causes the outer layers to expand even further and generates a strong convective zone that brings heavy elements to the surface in a process called the first dredge-up. This strong convection also increases the transport of energy to the surface, the luminosity increases dramatically, and the star moves onto the red-giant branch where it will stably burn hydrogen in a shell for a substantial fraction of its entire life (roughly 10% for a Sun-like star). The core continues to gain mass, contract, and increase in temperature, whereas there is some mass loss in the outer layers. If the star's