October 22, 2002 

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3. Spectrum

Figure 10.
Spectroscopic observations reveal double-peaked emission lines which hint at the presence of a rotating disk of hot gas. Analysis tools such as this were the primary means of determining that CV systems actually involved accretion disks.

Graphic created using Mathematica 4.2.

Figure 11.
Doppler tomography can construct "images" of these systems from their spectra even though the distance makes it impossible to resolve them in a normal telescope. The images are in velocity-space rather than normal X-Y space so understanding the image requires a fair amount of practice. The image that is created shows the distribution of light across the face of the accretion disk. Tomograms generated for other CV systems may show details such as the gas stream and the heated face of the secondary star.

Graphic created using Mathematica 4.2.

Jeffrey M. Bryant
Product Manager
Wolfram Research, Inc.
Wolfram Research, Inc.   Champaign, IL 61820