Astronomy Assignment: Stellar Nomenclature
Your Name______
Your Class Meeting Time ______
This assignment is due on Tuesday 21, July
Submit this cover sheet with your assignment.
Complete the assigned problems from the text listed below and address the Instructor Assigned Topic. Mathematical problems may be hand written. Write out the problem, show your work in solving the problem and state your answer in a complete sentence. Failure to complete all three of these tasks will result in less than full credit awarded. The Instructor assigned topic must be typed.
Review Questions from Chapter 11 in Astronomy Notes
1. Describe the procedure used to find distances to the nearby stars.
2. What do you need to know in order to get the scale of interstellar space in terms of kilometers or meters?
3. If the star-Sun distance = 30 parsecs, how far is the star from the Earth?
4. If you measure the parallax of a star to be 0.1 arc second on Earth, how big would the parallax of the same star be for an observer on Mars (Mars-Sun distance = 1.5 A.U.)?
5. If you measure the parallax of a star to be 0.5 arc second on Earth and an observer in a space station in orbit around the Sun measures a parallax for the same star of 1 arc second, how far is the space station from the Sun?
6. If you can measure angles as small as 1/50 arc second, how far out can you measure star distances from the Earth using the trigonometric parallax method? How long do you have to wait between observations?
7. If you can measure angles as small as 1/50 arc second, how far out can you measure star distances from Jupiter (Jupiter-Sun distance = 5.2 A.U.) using the trigonometric parallax method? However, how long do you have to wait between observations? (Use Kepler's third law to find Jupiter's orbital period and divide by two.)
8. What does a magnitude interval of 5 correspond to in brightness? How about an interval of 1? How about an interval of 3?
9. Do bright things have larger or smaller magnitudes than fainter things?
10. How is apparent magnitude different from absolute magnitude?
11. Put the following objects (given with their apparent magnitudes) in order of brightness as seen from Earth (faintest first): Sun (-26.7), Venus (-4.4), Barnard's Star (9.5), Sirius (-1.4), Proxima Centauri (11.0).
12. What two things does luminosity depend on?
13. Two stars have proper motions of 0.5 arc seconds/year. Star (A) is 20 parsecs away and star (B) is 30 parsecs away. Which one is moving faster in space?
14. If our Sun has a surface temperature of 5840 K, how many times hotter than the Sun is the hottest O-type star? How many times cooler than the Sun is the coolest M-type star?
15. What is the range of temperatures found on the surface of main sequence stars?
16. What is the range of luminosities produced by main sequence stars? Compare them to the Sun (Watts are ridiculously small energy units to use).