USAAAO 2022, I кръг — Задача 12

• B

The Sun’s post-main-sequence evolution will begin when nuclear fusion exhausts the hydrogen in the core and a helium core forms. The Sun will then expand into a red giant. Eventually, the temperature of the degenerate helium core will become high enough to initiate triple-alpha helium fusion, leading to a runaway chain reaction in which much of the helium core is rapidly converted into carbon. This is known as the helium flash. After the helium flash, the Sun will enter the horizontal branch and then the asymptotic giant branch once the helium in the core has been exhausted. Finally, the Sun will shed off its outer layers in a planetary nebula and the remaining exposed core will become a white dwarf.

Answer: B