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     - The Universe
     - Asteroids
     - Types of Stars
     - Color
     - Galaxies
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Types of Stars
 Your Classifications
 Spectral Lines
 Identifying
 Other Types
 Follow Up Projects
 Your Results

Follow Up Projects

The Object Explorer and Get Plates tools offer you access to the spectra of many thousands of stars. Some stars in the SkyServer database do not fit easily into any spectral type.

You can also use SkyServer's SQL Search tool to get a list of all stars with certain spectral types, or in certain parts of the sky. See the interactive Searching for Data tutorial for more information.

Now, you are ready to use spectral types to conduct actual research projects in astronomy. Here are a few of possible follow up projects. Try one of these projects, or think of another question you would like to answer by classifying stars into spectral types.

Exercise 8. Find a star cluster in the database. Classify the stars in the cluster. Do you notice any distinct patterns of spectral types?

Exercise 9. The SDSS primarily looks away from the galactic plane. However, there are parts of the sky we are analyzing that are substantially closer to the galactic plane. Do you notice any differences in the types of stars you see in these different parts of the sky?

Exercise 10. Since temperature and color are related, it is possible to classify stars by their colors. This process is called photometric classification. There are a couple of ways to approach this problem. The easier way it to make a graph of spectral type vs. color, say g-r. Classify 40 to 50 stars by looking at their spectra. Now you can read the spectral type off the graph from the g-r value of the stars.

This technique breaks down for very red stars, however. A more advanced technique is to make an r-i vs. g-r graph. When you make this graph, assign each star type a different color on the graph. Then you can see exactly where each type of star lies in color space. Stars with similar g-r values can be separated by their r-i values!

E-mail us your findings. We'll look through all the results we receive, and we will post the best of them here!

Project designed by Robert Sparks

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