A star's evolutionary track is
A) its movement when plotted on a Hertzsprung-Russell diagram,as it evolves in luminosity and temperature.
B) its motion through the dark,dense cloud from which it was formed,marked by a visible channel swept free of dust and gas.
C) the line across the Hertzsprung-Russell diagram denoting stars identified as main-sequence stars.
D) its movement when plotted on a map of the galaxy as it takes part in the overall galactic rotation.

Question

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A star's evolutionary track is its movement on a Hertzsprung-Russell diagram, as it evolves in luminosity and temperature. This diagram plots a star's surface temperature against its luminosity, allowing astronomers to trace a star's evolution throughout its lifetime. For example, as a star exhausts its fuel and its core contracts, its temperature increases and its luminosity decreases, causing it to move from the main sequence to become a red giant, and eventually to a white dwarf or supernova. The evolutionary track on the Hertzsprung-Russell diagram allows astronomers to study the life cycles of stars and make predictions about their future evolution.

A Star's Evolutionary Track Is