Measuring stellar distance using parallax angles and the Hertzsprung-Russell diagram

Hurricanes and NASA Problems

Finding the Distance to Stars Using the Parallax Angle

Given the above equation and information provided, about how far away is HT Cas?

133 parsecs

parsecs

parsecs parsecs

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).

light years

217 light years

434 light years

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% 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).

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.

Figure 5. Hertzsprung-Russell diagram.

(Lutgens, Tarbuck, & Tesa, 2010)1. Main Sequence stars can be classified according to which characteristics? What are the characteristics of our Sun?

The primary characteristics of Main Sequence stars are mass and temperature. The sun has a surface temperature of approximately 6,000K. It's absolute magnitude is approximately +3.5. It's spectral class is close to G. Its luminosity is 1.

2. 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?

The red main sequence stars can be found with a surface temperature of between 3000K-4000K. Some of the white dwarfs have a luminosity about 100 times less than that of the Sun.

3. Briefly describe the solar evolution time-line of a common star like our own from formation through collapse.

The main part of the solar evolution time-line of a common star like our own is its maturity phase. From the beginning of collapse to adulthood, this star requires approximately 50 million years to mature (Nasa, 2016). It will stay mature for about 10 billion years. Stars continue their existence by fusing hydrogen from their core. When all of the hydrogen within the core is gone, it begins to collapse into itself.