Cypress College ASTR 116 Homework
Astronomy 116, Homework CHAPTER 10 (A) Measuring the Stars. Due:
Print Last, First Name and date on the small Scantron in INK. Print
your last name in BIG BLOCK letters on the back of the Scantron.
Use a No. 2 pencil to fill out Scantron. Read the chapter.
Look at the videos and simulations in the CD-ROM. Answer all True/False and
Fill in the Blank questions. Then answer the following questions
and turn in your Scantron only. Choose the best answer.
1. How long is the baseline in measuring stellar parallax?
- a) 1 AU
- b) 2 AU
- c) 1 light year
- d) 1 parsec
2. A star has a radial velocity of 30 km/s and a transverse velocity of
40 km/s. What is its total velocity relative to Earth?
- a) 10 km/s
- b) 35 km/s
- c) 50 km/s
- d) 70 km/s
3. Star A has higher luminosity than Star B, but is farther away.
Which has higher apparent brightness?
- a) Star A
- b) Star B
- c) Could be either, depending on their specific luminosities and
distances.
- d) Impossible to determine.
4. Stellar lifetime is proportional to
- a) mass times luminosity.
- b) mass over luminosity.
- c) luminosity over mass.
- d) None of the above.
5. What are the two most important intrinsic properties used to classify
stars?
- a) Luminosity and surface temperature.
- b) Distance and luminosity.
- c) Distance and surface temperature.
- d) Distance and color.
6. Which of the following is the most common type of star?
- a) White dwarfs.
- b) Red giants.
- c) Main Sequence.
- d) Supergiants.
7. What is the single most important characteristic in determining the
course of a star's evolution?
- a) Absolute brightness.
- b) Distance.
- c) Surface temperature.
- d) Mass.
8. What characteristic of the stars in a binary system can be determined
by knowing the period of the stars' common orbit and the distance between
them?
- a) Absolute brightness.
- b) Sizes of the stars.
- c) Surface temperature.
- d) Mass.
9. Why are star clusters almost ideal "laboratories" for stellar studies?
- a) The combined light of the stars makes them easier to see.
- b) Like our Sun, stars in clusters are always located in the plane
of the Milky Way Galaxy.
- c) Stars in clusters have the same age, similar composition, and
lie at approximately the same distance away.
- d) Stars in clusters are all relatively young and therefore shine
brightly.
10. A nearby star has a parallax of 0.2 arc seconds. What is its
distance?
- a) 0.2 pc
- b) 0.5 pc
- c) 2 pc
- d) 5 pc
11. Star A has the same luminosity as star B. Also, star A
is 3 times as far as Star B from Earth. Then star A is ______
as bright as star B as seen from Earth.
- a. 3 times
- b. 9 times
- c. 1/3
- d. 1/9
12. select the order of star color in increasing temperature from
cool to hot.
- a. yellow, blue, red
- b. blue, red, yellow
- c. red, yellow, blue
- d. red, blue, yellow
13. Star A is twice as hot as star B, then Star A is ___ as luminous
as star B.
- a. twice
- b. half
- c. 4 times
- d. 8 times
- e. 16 times
14. A binary star system has two stars where the low mass star orbits
the more massive star at a distance of 3 AU. They orbit each other with
a period of 2 years. Their combined mass in solar units is
- a. 6.75
- b. 0.15
- c. 0.89
- d. 1.13
15. The higher a star's mass, the ______ is its lifetime.
- a. longer
- b. shorter
- c. none of the above, lifetime is independent of mass.