Follow Up Projects
The Object Explorer and
Get Plates tools offer you access
to the spectra of nearly 20,000 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.
Find a star cluster in the database. Classify the stars in
the cluster. Do you notice any distinct patterns of spectral
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
Exercise 9. 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!