Credit: ESA

Newton's First Rainbow

Different atomic elements absorb and emit light in specific colors or energies. Breaking light into its component colors to determine the location of these energies allows astronomers to determine the presence of atomic emission or absorption lines, which allows them to determine an object's composition, temperature, density, and speed. The Reflection Grating Spectrometer (RGS) on the XMM telescope (recently christened the XMM-Newton Telescope) allows astronomers to spread X-ray radiation into its component wavelengths and probe the makeup of the X-ray emitting object (star, nebula, galaxy or black hole).

The picture above shows the RGS X-ray spectrum of the star HR 1099. The banana-shaped band in the inset shows the detected X-rays plotted as a function of the position on the Newton X-ray detector, while the graph shows the X-rays plotted according to their wavelength. X-ray emission lines show up as peaks in the graph. These emission lines correspond to various elements present in the source: the presence of different types of iron, oxygen carbon and neon can all be seen.

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Each week the HEASARC brings you new, exciting and beautiful images from X-ray and Gamma ray astronomy. Check back each week and be sure to check out the HEAPOW archive!

Page Author: Dr. Michael F. Corcoran
Last modified April 4, 2002