Part 1: Finding the Distance to Stars Using the Parallax Angle
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:
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:
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:
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
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
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
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:
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.
Why Hire a Professional Essay Writer from essayprohire
The quality of an essay is important
If you want to be successful in the essay writing world, it’s important to make sure that the quality of your work is high. A professional essay writer from us will be able to provide you with high-quality papers, and they will also have the experience necessary to write effective essays. This means that you won’t have to worry about any errors or problems with your essays – they will be perfect.
Our Customer service is top-notch
If you have a problem with your essay, or if you just need a little help writing it, then you should contact our customer service. Our customer service is always available to help you with whatever you need – from getting your essay correct to helping you with the grammar and punctuation. We’re here to help, so don’t hesitate to call us today!
Our offer on Unlimited Revisions
If you're looking for essaywriting help, then you should definitely consider getting help from a essaywritinghelpnow. However, if you're not sure what you need or whether you have the time or resources to do the research yourself, then you might want to consider getting unlimited revisions done by our team of experts. O
Our guarantee to Confidentiality
We understand the importance of confidentiality, and we will never share your personal information with anyone without your permission. That’s why we offer a one-year guarantee that your essays will remain confidential. If you decide that you no longer want us to write your essays, we will still respect your privacy and will destroy all the evidence that we had of your work.
We believe that it is important to have a reliable and trustworthy essaywriter. That’s why we offer a 100% satisfaction guarantee on all of our essays. We take the time to get to know our clients, and we will always make sure that our essays are of the highest quality. We understand that not everyone is happy with their first essay, so we want to make sure that you’re always satisfied with the results of our work.
Our punctuality and quality
At our company, we pride ourselves on our punctuality and quality. We understand that it can be difficult to get essays written on time, and we’re here to help you out! Our writers are always available to help you with your essay, and we guarantee that you’ll receive the best possible product. We also have a strict no-nonsense policy when it comes to plagiarism, so you can be sure that your essay will be of the highest quality.
Try it now!
How it works?
Follow these simple steps to get your paper done
Place your order
Fill in the order form and provide all details of your assignment.
Proceed with the payment
Choose the payment system that suits you most.
Receive the final file
Once your paper is ready, we will email it to you.
So much stress and so little time? Take care of yourself: let us help you with your tasks. We offer all kinds of writing services.
No matter what kind of academic paper you need and how urgent you need it, you are welcome to choose your academic level and the type of your paper at an affordable price. We take care of all your paper needs and give a 24/7 customer care support system.
Admission and Business Papers
An admission essay is an essay or other written statement by a candidate, often a potential student enrolling in a college, university, or graduate school. You can be rest assurred that through our service we will write the best admission essay for you.
Editing and Proofreading
Our academic writers and editors make the necessary changes to your paper so that it is polished. We also format your document by correctly quoting the sources and creating reference lists in the formats APA, Harvard, MLA, Chicago / Turabian.
If you think your paper could be improved, you can request a review. In this case, your paper will be checked by the writer or assigned to an editor. You can use this option as many times as you see fit. This is free because we want you to be completely satisfied with the service offered.