NAVIGATING THE HR DIAGRAM SIMULATION

Use the H-R Diagram Simulation and outside sources to answer the Simulation and Lab Questions (below). You will also be asked questions where you will need to consult other sources. Keep track of our sources so you can easily include APA citations for any outside source used. For some of the questions, you can refer to the H-R Diagram shown above in these lab instructions. You may also use the below as a reference image.

Image 3: H-R Diagram from NAAP Labs.
https://d1lexza0zk46za.cloudfront.net/astronomy/simulations/HR_Diagram/index.html

SIMULATION AND LAB QUESTIONS

1. Near the bottom right corner, click on the button to display the “nearest stars." Describe the relationship in terms of temperature, luminosity, and radius of the nearest stars to the location of the Sun on the diagram. Which luminosity group(s) do these stars lie in?
2. Click off the “nearest stars”, and now click on “brightest stars." Describe the relationship in terms of temperature, luminosity, and radius of the nearest stars to the location of the Sun on the diagram. Which luminosity group(s) do these stars lie in?
   The next series of questions will ask you to move the red crosshairs on the diagram to different spots within the diagram to understand the evolution of our Sun and the changes that it will experience with time.
3. The Sun as it ages will grow in size and move off of the main sequence into an area of the diagram called the “instability strip." Research and briefly describe in your own words what the characteristics of the instability strip are. And list the types of stars that can be found in the stability strip. Be sure to properly cite your sources.
4. Move the crosshair into the instability strip, based on your research, so it is approximately in the middle of the group. Write on a slip of paper your name and the date.
    Hold the paper with your name next to the image on your computer and take a photo. Insert this into your lab report.
5. When it is in the instability strip, describe the changes that will occur with the Sun in terms of color, temperature, luminosity, and radius.
    This data can be gathered from the simulation-based on where your crosshairs are positioned.
    Briefly describe in your own words why these changes are occurring. Remember to supply your sources.
6. The next stage in the life of the Sun as it ages is the “Red Giant” luminosity class. Move the crosshair to the Red Giant class (a good spot would be just above the “an” in "Giants III" on Image 3 above). Describe the changes that will occur with the Sun in terms of color, temperature, luminosity, and radius.
7. The last stage in the life of the Sun as it ages is the “White Dwarf” luminosity class. Move the crosshair to the White Dwarf class (a good spot would be just above the “s” in "White Dwarfs" on Image 3 above). Describe the changes that will occur with the Sun in terms of color, temperature, luminosity, and radius.
8. As a White Dwarf, the Sun has decreased significantly in size. What happened between the Red Giant and White Dwarf classes to cause this? (Consult outside sources.)
9. Our Sun, however, is not big enough to be a Super Giant star, this only happens to the very highest mass stars. Move the crosshair back to the main sequence but to an area of R=10sun (a good spot would be just above the “rf” in "Dwarfs (V)" on Image 3 above). Describe the differences between this star and our Sun in terms of color, temperature, luminosity, and radius.
10. This star, from Question 3g, will become a Super Giant. Move the crosshair into the “Super Giant” class (a good spot would be just above the “gi” in "Supergiants (I)" on Image 3 above). Describe the differences with this star in terms of color, temperature, luminosity, and radius.
11. In a paragraph (minimum of 50 words) summarize what you have learned from both Parts 1 and 2 of this laboratory activity. What are some implications for the Earth as the Sun ages and moves through the different phases of its evolution?

Sample Solution