Sun and Stars Review
1. A star cluster made of thousands of old stars is called a globular cluster.
2. An irregularly shaped cluster with lots of heavy elements is called an open cluster.
3. The most common type of variable star is a long period variable.
4. Variable stars that show the period / luminosity relationship are called Cephid Variables.
5. Variable stars with short, regular periods are called RR lyrae variables.
6. Explosions from areas around sunspots are called Coronal Mass ejections.
7. Are sunspots cooler or warmer than surrounding areas of the sun? Cooler
8. When stars are placed in categories based on the type of EMR they emit the classes are referred
to as Spectral types.
9. What spectral type is the sun? G
10. Which spectral type of star is the brightest? M
11. Different stars emit different amounts of light. How bright a star is at a distance of 33 light years
is referred to as a star’s absolute magnitude.
12. How bright a star appears to be in the night sky, regardless of distance, is called its apparent
magnitude.
13. What graph plots stars by characteristics of temperature and brightness? HR Diagram
14. Stars spend the vast majority of their life on the diagonal band of an HR diagram. This band is
called the Main Sequence
15. Binary stars:
A pair of stars that appear to be close together but are actually many light years apart are called
a double star.
A pair of stars that travel together but each remains visible visual binary
Binary stars that vary in brightness because one passes in front of the other eclipsing binary
A binary pair that seems to have an invisible companion and thus appears to wobble in the sky is
called an astrometric binary.
16. Magnetic storms on earth are caused by solar flares.
17. What is the outermost level of the Sun (‘s atmosphere)? corona
18. What is the visible layer of the sun called? photosphere
19. What layer of the sun produces all of the energy emitted by the sun? core
20. What is the spiky layer of the sun just above the visible layer? chromosphere
21. The peak wavelength of radiation from the sun corresponds to what portion of the
electromagnetic spectrum? Yellow-orange (visible light)
22. Why does the surface of the sun appear splotchy? convection induced temperature differences
23. Based on the regions of the sun we can observe, it appears to be about 94% Hydrogen.
24. When a gas is heated so much that its electrons are ripped from the nuclei and it becomes an
electrically neutral soup of charged particles it is called a plasma.
25. The corona is substantially hotter than the photosphere. Because of this it emits energy chiefly
in a much higher frequency than the photosphere. Most of the energy from the corona is what
type of electromagnetic radiation? X -rays
26. Charged particles that have escaped the sun and are streaming through the solar system are
collectively called the solar wind.
27. Relatively dark regions of the photosphere are called sunspots.