I. For each question below, answer T for TRUE or F for FALSE.
F: 1. Since higher mass stars have more hydrogen fuel,
they last longer than low mass stars. (higher mass makes
gravity stronger, so massive stars must fuse hydrogen
more quickly to maintain hydrostatic equilibrium)
T: 2. When massive stars run out of hydrogen to fuse,
they fuse helium and higher elements. (4He and
elements with more protons [p+'s] and neutrons [n's]
require higher temps. to fuse, so core temp. must be HIGHER,
which requires more massive stars)
F: 3. Eventually, the Sun will explode
and turn into a black hole. (Sun will turn into white dwarf
which will fade into a black dwarf.)
T: 4. The primary reason stars evolve differently is that their masses differ.
II. For each question, circle the answer that applies.
1. Immediately after a star runs out of hydrogen to burn,
it can't maintain hydrostatic equilibrium, and (contracts/expands).
(GRAVITY wins when fusion rate decreases)
2. So heat and pressure build until (hydrogen/iron) fuses in a
shell around its core. (A: HYDROGEN; stars cannot steadily
fuse iron)
3. Fusion in the shell causes the star to (contract/expand).
(EXPAND)
4. Fusion in the shell also causes the star to become
(brighter/dimmer).
(BRIGHTER -- fusing H is outside of core, so photons
have an easier time escaping = star gives off more light)
5. A star in this state is a (main sequence/red giant) star.
(it's COOL and BIG, so a RED GIANT)
III. Match the type of star with its "post-death" remnant: a) neutron star; b) black hole; or c) white dwarf.
1. a star with a mass greater than 25 solar masses: BLACK HOLE
2. a star with about one solar mass: WHITE DWARF
3. a star with a mass between 5 and 25 solar masses: NEUTRON STAR
IV. Match the type of star cluster with its properties: a) globular; b) open; or c) stellar association.
1. OPEN CLUSTER: thousands in our galaxy; contain hundreds of stars; stars can be red or blue; Pleides are an example
2. STELLAR ASSOCIATION: thousands are in our galaxy;
contain 5-50 stars; most stars are blue
3. GLOBULAR CLUSTER: only about 200 around our galaxy;
contain thousands of stars; most stars are old, cold, and red;
M13 is an example