Low-Mass Stars Can Ascend the H-R Diagram in Two Evolutionary

question 178

Multiple Choice

Low-mass stars can ascend the H-R diagram in two evolutionary phases called giant phases. What is the difference between them?

• A) In the first, the primary production of energy is from hydrogen burning in the core. In the second, the primary production of energy is from helium burning in the core.
• B) In the first, the primary production of energy is from hydrogen burning in a shell around the core. In the second, the primary production of energy is from helium burning in a shell around the core.
• C) In the first, the star's track on the Hertzsprung-Russell diagram lies along the red-giant branch. In the second, the track lies along the horizontal branch.
• D) During the first red-giant phase, the star moves up and to the right along the red-giant branch. During the second red-giant phase the star's track is down and to the left along the same red-giant branch.

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Definitions:

Iron

A metal element with the symbol Fe, known for its magnetic properties and widely used in construction, manufacturing, and biochemistry.

Isotope

Variants of a particular chemical element which differ in neutron number, and consequently in nucleon number.

Electrons

subatomic particles with a negative electric charge, found in all atoms, and acting as the primary carrier of electricity in solids.

Isotope

Variants of a particular chemical element that have the same number of protons but different numbers of neutrons in their nuclei.