What does the ISM (interstellar medium) mainly consist of?
Dust and low-density gas
No stars have been found with masses greater than 150 times our Sun
because
they would generate so much power that they would blow themselves apart.
Which of the following main sequence stars of different surface temperature
would you expect to have the greatest mass?
33,000 K
Which of the following statements about main sequence stars is not true?
All main sequence stars are gradually moving lower and to the right on the H-
R diagram.
A star is located near the lower right of an HR diagram – what does this tell
you about this star?
It is among the coolest and least luminous of the star plotted
At what point is a main–sequence star officially born?
When is becomes hot enough in its core to fuse hydrogen into helium.
Ona Hertzsprung-Russell diagram, where would we find stars that are cool and
luminous?
Upper right
On the main sequence, stars obtain their energy
By converting hydrogen to helium.
As a main sequence star aged it moves slightly (there’s that word again) on
the H-R diagram form its zero-age main sequence location owing to changes
in its temperature and luminosity. What are these changes?
It temperature decreases and its luminosity increases.
If a star at the same luminosity but its temperature increases what must
happen to its size?
It must decrease.
Which of the following statements about the H-R diagram is not true?
The graph plots mass on the vertical axis and temperature on the horizontal
axis.
On a Hertzsprung-Russell diagram, where would we find stars are cool and
dim?
Lower right
What is generally accepted as the range of mass for main-sequence stars?
0.1 to 150 solar masses
which of the following sequences correctly describes the stages of life for low-
mass star?
protostar, main-sequence, red giant, white dwarf
why is iron the heaviest element that can be produced by fusion in a giant
star?
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