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Charge exchange-induced X-ray emission from comet C/1999 S4 (LINEAR)
C M Lisse1, D J Christian, K Dennerl
1University of Maryland, Department of Astronomy, College Park, MD 20742, USA. lisse@astro.umd.edu
Science (New York, N.Y.)
|May 19, 2001
Summary
Soft x-ray observations revealed charge exchange emission in comet C/1999 S4 (LINEAR)
Area of Science:
- Cometary Science
- Plasma Physics
- X-ray Astronomy
Background:
- Comets are icy bodies that release gases and dust.
- Solar wind interactions with cometary comas can produce emissions.
- Previous studies have suggested x-ray emission from comets.
Purpose of the Study:
- To investigate soft x-ray emission from comet C/1999 S4 (LINEAR).
- To identify the source and characteristics of the observed x-ray emission.
- To understand the interaction between the solar wind and cometary coma.
Main Methods:
- Soft x-ray observations using the Chandra X-ray Observatory.
- Analysis of the x-ray emission spectrum and morphology.
- Contemporaneous soft x-ray light curve analysis using the Extreme Ultraviolet Explorer.
Main Results:
- Detection of crescent-shaped x-ray line emission extending 300,000 km from the nucleus.
- Identification of six spectral lines (320-670 eV) attributed to charge exchange.
- Correlation of increased cometary emission with a solar flare event.
Conclusions:
- Charge exchange between highly ionized solar wind ions and cometary neutrals is confirmed as the source of x-ray emission.
- The observed emission provides insights into solar wind composition and cometary coma properties.
- Cometary x-ray emission is variable and influenced by solar activity.
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