University of Kansas

X-Ray Emission in the Solar System

Image: Jovian soft X-rays from ROSAT; courtesy of J. H. Waite.


Temporal and Spatial Variations of Heliospheric X-Ray Emissions Associated with Charge Transfer of the Solar Wind with Interstellar Neutrals

I. P. Robertson,1 T. E. Cravens,1S. Snowden,2 and T. Linde3
1University of Kansas, Department of Physics and Astronomy, Lawrence, KS 66045
2NASA Goddard Space Flight Center, Greenbelt, MD 20771
3University of Chicago, Chicago, IL 60637

(The final version of this paper appeared in Space Science Reviews, 97, 401, 2001.)

Abstract with link to full article on Space Science Reviews website.

Abstract. A simple model has been developed that demonstrates that heliospheric x-ray emission can account for about 25-50 percent of observed soft x-ray background intensities. Similar to cometary soft x-ray emission, these x-rays are thought to be produced in the heliosphere due to charge transfer collisions between heavy solar wind ions and interstellar neutrals. A more complex model has now been developed to take into account temporal and spatial variations of the solar wind and interstellar neutrals. Measured time histories of the solar wind proton flux are used in the model, and the results are compared with the "long-term enhancements" in the soft x-ray background measured by ROSAT for the same time period.

Acknowledgments. NASA Planetary Atmospheres grant NAG5-4358 and NSF grant ATM-9815574 at the University of Kansas are gratefully acknowledged.


Figure 1. November 21 - December 17, 1990, proton flux and ROSAT LTEs.
Figure 2. Correlation between proton flux and ROSAT LTEs.
Figure 3. Map of He and H densities. Units are keV cm-2 s-1 sr-1. The short lines point away from the gradient in the x-ray intensity.

Last modified Sept. 8, 2006
Tizby Hunt-Ward