Mulitply choice and short answer

 

 

 

Part 1: Finding the Distance to Stars Using the Parallax Angle

 

 

 

Instructions:

 

 

 

Read Chapter 15 and Appendix D (pp. 543-545) in the textbook and the background information below.

 

Answer the three questions at the bottom directly in this lab worksheet. 

 

 

 

This NASA web page provides additional explanation and allows you to check your answer:

 

 

 

http://imagine.gsfc.nasa.gov/features/yba/HTCas-size/parallax3.html

 

 

 

Background:

 

 

 

Stellar Parallax is the apparent shift in the location of a star due to the orbit of the Earth.  In other words, the star will appear to be in a different place depending on the line of sight from the Earth. By knowing the diameter of Earth’s orbit and by measuring the angle of apparent shift (the parallax angle), astronomers can calculate the distance to the nearby stars using trigonometry. This method has been used for centuries. The ancient Greeks were able to measure some of the closest stars this way. Today, sophisticated telescopes have greatly enhanced this method. Figure 1 is a graphic from your textbook showing how this works:

 

 

 

 

Assignment:

 

 

 

For this assignment, you will determine the distance to a star, “HT Cas”, using the method of stellar parallax. Figure 2 and 3 below are photos of HT Case, taken six months apart:

 

Image of HT Cas taken 06/96
Fig 2. Image of HT Cas taken 06/96

Image of HT Cas taken 12/96
Fig. 3. Image of HT Cas taken 12/96

 

 

 

When we super-impose these photos, we get the following image (figure 4):

 

 

 

 

       
   
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

You can see that the position of the star appears to have changed over the six-month time period.  However, it is actually the angle from which the photos were taken that has changed.  During that 6-month period, the Earth moved from one side of the sun to the other.

 

 

 

Using a stellar astrometric catalog, we find that the two stars closest to HT Cas are a distance of 0.01 arcseconds apart. Based on this information, we can estimate that the angle of shift of HT Cas (the parallax angle) to be approximately 0.015 arcseconds apart.

 

 

 

We also know that the radius of the Earth’s orbit is 1.0 A.U. (astronomical units).

 

Using these two measurements, we can then determine the approximate distance to HT Cas using the following equation:

 

 

 

 

d= distance to HT Cas

 

a=radius of the Earth’s orbit

 

p=parallax angle

 

 

 

1.     (10 points) Given the above equation and information provided, about how far away is HT Cas? 

 

a.     133 parsecs

 

b.    67 parsecs

 

c.     33 parsecs

 

d.   

 

 
  Text Box: Answer:

 


0.015 parsecs

 

 

 

2.     (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).

 

a.     0.025 light years

 

b.    217 light years

 

c.     434 light years

 

d.    219 light years

 

 

 

 
  Text Box: Answer:

 

 

 

3.     (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?

 

Main sequence stars can be classified according to their apparent magnitude and brightness, characteristics of our sun is between 5000k and 6000k in temperature appears yellow.

 

 

 

 

 

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. 

 

Calculate the price of your order

550 words
We'll send you the first draft for approval by September 11, 2018 at 10:52 AM
Total price:
$26
The price is based on these factors:
Academic level
Number of pages
Urgency
Basic features
  • Free title page and bibliography
  • Unlimited revisions
  • Plagiarism-free guarantee
  • Money-back guarantee
  • 24/7 support
On-demand options
  • Writer’s samples
  • Part-by-part delivery
  • Overnight delivery
  • Copies of used sources
  • Expert Proofreading
Paper format
  • 275 words per page
  • 12 pt Arial/Times New Roman
  • Double line spacing
  • Any citation style (APA, MLA, Chicago/Turabian, Harvard)

Our guarantees

Delivering a high-quality product at a reasonable price is not enough anymore.
That’s why we have developed 5 beneficial guarantees that will make your experience with our service enjoyable, easy, and safe.

Money-back guarantee

You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.

Read more

Zero-plagiarism guarantee

Each paper is composed from scratch, according to your instructions. It is then checked by our plagiarism-detection software. There is no gap where plagiarism could squeeze in.

Read more

Free-revision policy

Thanks to our free revisions, there is no way for you to be unsatisfied. We will work on your paper until you are completely happy with the result.

Read more

Privacy policy

Your email is safe, as we store it according to international data protection rules. Your bank details are secure, as we use only reliable payment systems.

Read more

Fair-cooperation guarantee

By sending us your money, you buy the service we provide. Check out our terms and conditions if you prefer business talks to be laid out in official language.

Read more