Question

For a low-mass star, the stage following the giant star stage is the ______ stage?

1) Main sequence
2) White dwarf
3) Supernova
4) Neutron star

Answer 1

For a low-mass star, the stage following the giant star stage is the white dwarf stage. This occurs after the star has passed through the main sequence and red giant phases, subsequently shedding its outer layers, and leaving a core supported by degenerate electron pressure.

Step-by-step explanation:

For a low-mass star, the stage following the giant star stage is the white dwarf stage. Let's describe the evolution of a star with a mass like that of the Sun, starting from the main sequence phase:

1. The star spends the majority of its life in the main sequence phase, fusing hydrogen into helium in its core.
2. Once the hydrogen in the core is exhausted, the core contracts and heats up, leading the outer layers to expand and cool, forming a red giant.
3. After the red giant phase, the star will shed its outer layers, often creating a planetary nebula, while the core collapses into a white dwarf.

Stars up to about 8 Msun can shed enough mass through their life cycle to reach this white dwarf stage, with mass less than the Chandrasekhar limit of 1.4 Msun. The intense pressure exerted by degenerate electrons in the white dwarf supports it against further collapse. Overtime, the white dwarf will cool and fade away as a black dwarf, but this process is longer than the current age of the universe.

When considering a star that begins with a larger mass, such as 5 Msun, and ends as a white dwarf of about 0.8 Msun, it has lost mass during the red giant phase and possibly during a planetary nebula stage, mainly through stellar winds and the ejection of its outer layers.