d= distance to HT Cas
of the Earth’s orbit
angle
(10 points) Given the above equation and information provided, about how far away is HT Cas? 133 parsecs67 parsecs33 parsecs
0.015 parsecs
- (10 points) Your answer was calculated in parsecs. Given that 1 parsec = 3.2616 light years, about what is the distance to HT Cas in light years? (Your answer in parsecs X 3.2616 light years = The Distance to HT Cas in light years).
- 0.025 light years
- 217 light years
- 434 light years
- 219 light years
- (30 points) Based on your answer, do you think this is a star that we might be able to send a space probe to? Why or why not? Support your answer.
Part 2: Using a Hertzsprung-Russell Diagram
Instructions: After reading the Unit VIII lesson, click here to access the NASA web page “Stars” and answer the questions below using Figure 5. You can also copy and paste the web address into your browser:
http://science.nasa.gov/astrophysics/focus-areas/how-do-stars-form-and-evolve/
Background:
Notice that the stars in Figure 5 are not uniformly distributed. Rather, about 90 percent of all stars fall along a band that runs from the upper-left corner to the lower-right corner of the H-R diagram. These “ordinary” stars are called main-sequence stars. As you can see in Figure 5, the hottest main-sequence stars are intrinsically the brightest, and, conversely, the coolest are the dimmest. The absolute magnitude of main-sequence stars is also related to their mass. The hottest (blue) stars are about 50 times more massive than the Sun, whereas the coolest (red) stars are only 1/ 10 as massive. Therefore, on the H-R diagram, the main-sequence stars appear in decreasing order, from hotter, more massive blue stars to cooler, less massive red stars (Lutgens, Tarbuck, & Tasa, 2014).
Assignment: Use Figure 5 to answer the questions. Once all questions have been answered for both part 1 and part 2, save this worksheet with your last name and student number and upload to Blackboard for grading.
1. (10 points) Main Sequence stars can be classified according to which characteristics? What are the characteristics of our Sun?
2. (10 points) Which main sequence stars can be found with a surface temperature of between 3000K-4000K? Which stars have a luminosity about 100 times less than that of the Sun?
3. (30 points) Briefly describe the solar evolution time-line of a common star like our own from formation through collapse.
