When all of the hydrogen of the Sun is used up, it will turn into a _________?
So, nuclear fusion reactions will begin to occur? Would helium fill the blank?
This site seems to have a good explanation.
http://curious.astro.cornell.edu/question.php?number=48
When all of the hydrogen in the Sun is used up, it will turn into a different type of star known as a red giant. Let me explain how scientists reach this conclusion.
To understand the life cycle of stars, we can start with our Sun. The Sun is currently in the main sequence phase, where hydrogen atoms in its core undergo nuclear fusion to form helium. This fusion process releases an incredible amount of energy, which is why the Sun shines so brightly.
As the Sun consumes its hydrogen fuel, the nuclear fusion reactions slow down, causing the core to contract and the outer layers to expand. This expansion leads to the Sun becoming a red giant. In this stage, the outer layers of the Sun will cool and glow red, hence the name "red giant."
During the red giant phase, the Sun will become much larger, potentially engulfing nearby planets like Earth. However, the specifics of this process are still not fully understood and require further scientific investigation.
Eventually, the red giant phase will come to an end, and the Sun will shed its outer layers, forming a beautiful cloud of gas and dust called a planetary nebula. The exposed core of the Sun, known as a white dwarf, will remain and gradually cool off, emitting less and less energy over time.
So, to summarize, when all of the hydrogen in the Sun is used up, it will become a red giant before shedding its outer layers and leaving behind a white dwarf.