Spectral Types of Stars

The Java applet below allows you to plot observed spectra of stars of several spectral types. You can then compare them with blackbody spectra of adjustable temperature.

This applet is part of some sample notes from "Life in the Universe", a distance learning course in astronomy offered by the Jodrell Bank Observatory of The University of Manchester. More information on these courses is available here.

The applet has the following features:

If your browser recognized the applet tag, you would see an applet here.

Work through the following exercises:

Click for answer 1. Select spectral type G5V. Choose a fiducial wavelength around 7000 Angstroms by clicking on the spectrum of the star at about that wavelength. Adjust the blackbody temperature until you get the best fit to the observed spectrum on the right side of the plot i.e. where the flux is declining towards higher wavelengths. Is this temperature consistent with what you expected?

Click for answer 2. Suggest why the blackbody curves seem to fit best to the long wavelength end of the observed spectra?

Return to Life in the Universe Properties of Stars web pages.
The graph plotting in this applet is achieved using the Ptplot package.