Relate hydrostatic equilibrium to the star's mass, composition, and evolution off the main sequence
What will be an ideal response?
Hydrostatic equilibrium means that the inward force of gravity, a product of the star's mass, is exactly balanced by the outward radiation pressure of its thermonuclear reactions; as long as the hydrogen supply is abundant, this balance can be maintained, and the star is stable on the main sequence. Once the core helium content grows, and the hydrogen burning shell expands, this extra radiation temporarily overwhelms gravity, and the star begins swelling into its giant stage of evolution.
You might also like to view...
Applications to Astronomy: Many supernovas are thought to result in
A. neutron stars. B. red giant stars. C. regular stars like our sun. D. white dwarfs.
Match the words in the left-hand column to the appropriate blanks in the sentences in the right-hand column. Use each word only once.
Saturn, Earth, Mars, Venus, Uranus, Mercury, Jupiter, Neptune
1. ____________ has a rotational axis that is tilted so much it lies nearly in the plane of its orbit.
2. ____________ is the planet with the highest average surface temperature.
3. The planet that orbits closest to the Sun is __________.
4. The only rocky planet to have more than one moon is ___________.
5. ___________ is the jovian planet that orbits closest to the Sun.
6. Most of the surface of _________ is covered with liquid water.
7. ___________ is about 30 times as far from the Sun as our own planet.
8. The planet with the lowest average density is ___________.
How does Rigel, a bluish star, surface temperature compare to Betelgeuse, a reddish star.
A. Rigel's surface temperature is less than Betelgeuse's. B. Rigel's surface temperature is greater than Betelgeuse's. C. They have the same surface temperature because they are both members of the constellation Orion. D. It is impossible to say without knowledge of the sizes of the stars.
When the chromosphere can be seen during a solar eclipse, it appears
A) invisible. B) violet. C) blue. D) yellow. E) red.