Question

The structure of the deep interior of a low-mass star near the end of its life is a(n)

A) carbon-oxygen core, a shell around the core where helium nuclei are undergoing fusion, and a surrounding shell of hydrogen.
B) inactive hydrogen core and a helium shell undergoing nuclear fusion surrounded by a carbon-oxygen shell.
C) turbulent mixture of hydrogen, helium, carbon, and oxygen in which only helium continues to undergo nuclear fusion.
D) helium core surrounded by a thin hydrogen shell undergoing nuclear fusion with very small concentrations of heavier nuclei.

Answer 1

The structure of a low-mass star near the end of its life includes a carbon-oxygen core, a shell of helium fusion, and a shell of hydrogen fusion.

Step-by-step explanation:

The structure of the deep interior of a low-mass star near the end of its life is a carbon-oxygen core, a shell around the core where helium nuclei are undergoing fusion, and a surrounding shell of hydrogen. This structure is illustrated in Figure 22.17: Layers inside a Low-Mass Star before Death, where the layers include, from the center outward, the carbon-oxygen core, a layer of helium hot enough to fuse, a layer of cooler helium, a layer of hydrogen hot enough to fuse, and then cooler hydrogen beyond. As the energy flows outward from the two fusion shells, the outer regions of the star begin to expand, and the star moves back to the red-giant domain on the H-R diagram for a short time before its final burst of glory.