Observed Spectra
The computer simulation you did in Explore 2 assumes that all
the light stars emit comes from thermal radiation. In reality, stars
emit light for other reasons as well (see the
Types of Stars project to learn more about these reasons).
The SDSS's spectrograph has measured spectra for about 154,925 stars.
In the next Explore exercise, you will study some of these spectra
to learn whether or not they really look like the simulated spectra
you studied earlier.
Explore 4.
Use the
Plate Browser tool to look up the spectra of several stars. Select
a plate from the drop-down menu, then select a "star" link to see a
spectrum. Be sure you pick a spectrum of a star.
How do the spectra of stars in the SDSS compare to thermal radiation
curves? What are the similarities? What are the
differences? Can you see a peak wavelength for these stars? |
The Other 90,617,060 Stars
In the last two exercises, you have learned how to find the temperature
of a star from the peak wavelength of its spectrum. The SDSS has measured
spectra for 154,925 stars. But it has also taken images of almost
91 million stars! What can astronomers learn about those other
90,617,060 stars by studying their colors? Read on to find out.
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