Our Sun does not have enough mass to explode as a supernova. Instead, in 4-5 billion years it will enter its red giant phase, expanding as the hydrogen fuel in the core is consumed. Then it will start to fuse helium and the core temperature will rise to 3×108 K. While it is likely that the expansion of the outer layers of the Sun will reach the current position of Earth's orbit, recent research suggests that mass lost from the Sun earlier in its red giant phase will cause the Earth's orbit to move further out, preventing it from being engulfed. Following the red giant phase, giant thermal pulsations will cause the Sun to throw off its outer layers forming a planetary nebula. The Sun will then become a white dwarf, slowly cooling over eons. This scenario is typical of small stars: our Sun appears to be a fairly run-of-the-mill star.