Follow Up Projects
Another interesting phenomenon sometimes seen in SDSS data is
that of a multiple star system. Sometimes the "star" spectrum you see
actually comes from two or more stars orbiting each other. You may notice
some spectra with two or more peak wavelengths, indicating two or more temperatures. These
peaks could be due to the fact that you are actually looking at a multiple
star system, and the stars have different temperatures. You may find
a white dwarf orbiting a type G or K star, for example. You always need
to keep in mind that any star you see may actually be a multiple star
system.
The image below shows the spectrum of a double star system - notice the two
peaks in the thermal radiation curve. Astronomers estimate that about half the stars in the sky are part of
multiple star systems; however, if the smaller "companion star" is very faint and
close to the larger star, you may not detect its spectrum.
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Click on the image to see it full size |
The Get Spectra and
Plate Browser tools offer you access to the spectra of
literally thousands of stars. Some stars in the SkyServer database do not
fit easily into any spectral type.
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.
Research Challenge 1. Find a star cluster in the database.
Classify the stars in the cluster. Do you notice any distinct patterns of spectral
types? |
Research Challenge 2. The SDSS primarily looks away from the plane of
the Milky Way.
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? |
Research Challenge 3. Look through the database for double stars.
How frequently do you find them? What are some of the common combinations you
find? How easy is it to separate their spectra? |
E-mail us your findings. We'll review all the results we get,
and we will post the best of them on these pages! |
