Stellar Evolution

Pre - Lab

Read the NASA article entitled The Life Cycle of Stars

As you read the article draw a rectangle around the star stages (nebula, protostar, main sequence star, red giant, planetary nebula, white dwarf, super-nova, neutron star, black hole)

Next underline the key characteristics for each phase.

Check out these "human stars". Can you rank them in age from youngest to oldest?

http://btc.montana.edu/ceres/html/LifeCycle/starsunhuman.html 

You probably found that the humans are relatively easy, because you are familiar with this species :)  Now can you do the same thing with stars. Try it, based on what you now know. Then do a little research by using control click to follow the hyperlink.  Write the name of the star on the table below the picture.

 Write the name of each star in the table below:

If you are not familiar with the Hertzprung - Russell diagram, use this link to practice plotting temperature vs spectral class.

http://www.smv.org/jims/hr/hrEX.htm

After you finish, compare your graph to the Hertzsprung - Russell Diagram on page 664 of the text.  Sketch the locations of 1) main sequence stars, 2) white dwarfs, and 3) red giants. Remember that main sequence stars have a linear relationship between temperature (or spectral class) and luminosity. If you can find the temperature and luminosity of an unknown star, you will be able to find its location on this Hertzsprung - Russell Diagram and therefore its stage of stellar evolution.

 If you know the color of a star, you can estimate a star's temperature.

1. For the stars on table 1.1, use the color of the peak wavelength and Wien's Law to estimate the temperature of the stars in Kelvin

            Wien's Law:               Wavelength = .00288

                                                                        Temperature

* Divide up the work. Each group member should pick two or three colors to calculate and plot.

2. Use semi-logarithmic graph paper to make a Hertzsprung-Russell Diagram by plotting luminosity vs. temperature. Set it up like the graph on pg. 664 of your text.( Ignore the Absolute magnitude and the spectral class axes) Use a colored pencil to circle each data point with the color of the star. (Let white = pencil lead)

3.  Now  identify the red giants and supergiants, white dwarfs and main sequence stars. If necessary. refer to figure 24.5 in unit one of your text (pg 664).  Label each of these groups on your graph. Remember, main sequence stars have a linear relationship between luminosity and temperature.

4. Now to see the stars that you will classify, go to http://btc.montana.edu/ceres/html/LifeCycle/starsunbigstar.html  

The images on this page are pictures of the 10% of stars that are not in the main sequence. 

After filling out Table 1.2, write each "star's"  letter on the diagram in the appropriate square.

Table 1.1

 Stellar Evolution

Read the NASA article "Life Cycle of a Star" and write a working definition of these terms. You will use these terms to sequence stars.

* You will use this page to do item # 4 on page 3.

Nebula – This accumulation of gas and dust exists between stars. 

Protostar

Main Sequence Star

White Dwarf

Red Giant

Red Supergiant

Planetary Nebula

Supernova Explosion

Neutron Star

 Table 1.2

sequence _____     _____     _____     _____     _____     _____     _____     _____