Download Name: Notes – #45 The Diverse Sizes of Stars 1. A Hertzsprung

Name: ___________________________
Notes – #45 The Diverse Sizes of Stars
1. A Hertzsprung-Russell diagram plots the _____________ on the y-axis and the
__________________ on the x-axis.
2. The Sun has a luminosity of ____ solar luminosity and a temperature of _______ deg K.
3. Hotter star emit much _______ energy than cooler stars per emitting area. The amount
of energy stars emit is proportional to their surface temperature to the ______ power.
4. A star that is twice as hot as another star with the same surface area emits ______
times more energy per second.
5. What is the equation for the luminosity of a star?
6. Super giants tend to have surface temperatures cooler than the sun but emit 104 time or
more energy than the Sun. Why is this true?
7. The size of the star Betelgeuse in the constellation Orion is approximately the same size
as ____________’s orbit around the Sun.
8. What stars have the same temperature of the Sun, but emit much less energy per second?
9. A white dwarf is about the same size as the __________.
10. It is _______________ that determines most properties of stars; their radii, their
luminosity, their surface temperatures, etc.
11. Some stars are not perfectly spherical. They are elongated at their equator because of
their rapid ________________.
12. True or False? All stars have a fixed and constant radius.
13. True or False? All stars have a constant brightness.
14. Polaris A is a ___________________ variable star.
15. Henrietta Levitt noticed that intrinsically brighter Cepheid variables have
_______________ periods than intrinsically fainter ones. By knowing the intrinsic
brightness of Cepheid variables, allows astronomers the ability to determine the
__________________ to galaxies.
16. Astronomer can determine the _________ of exoplanets (i.e. planets orbiting another
start) when these planets transit (i.e. pass in front of) their parent star. You don’t know
the size of the planet unless you know the _________ of the star.