Editing Coma (comet) (section)

==X-rays==
[[File:PIA02118.jpg|thumb|150px|Tempel 1 in X-ray light by [[Chandra X-ray Observatory|Chandra]]]]
Comets were found to emit [[X-rays]] in late-March 1996.<ref>
{{cite web
 |title=First X-Rays from a Comet Discovered
 |url=http://heasarc.gsfc.nasa.gov/docs/rosat/hyakutake.html
 |publisher=[[Goddard Spaceflight Center]]
 |access-date=2006-03-05
}}</ref> This surprised researchers, because X-ray emission is usually associated with very [[black-body radiation|high-temperature bodies]]. [[Thomas E. Cravens]] was the first to propose an explanation in early 1997.<ref>{{cite journal
| last = Cravens
| first = T. E.
| date = 1997
| title = Comet Hyakutake x-ray source: Charge transfer of solar wind heavy ions
| journal = Geophysical Research Letters
| volume = 24
| issue = 1
}}</ref> The X-rays are thought to be generated by the interaction between comets and the solar wind: when highly charged [[ions]] fly through a cometary atmosphere, they collide with cometary atoms and molecules, "ripping off" one or more electrons from the comet. This ripping off leads to the emission of X-rays and [[far ultraviolet]] [[photon]]s.<ref>
{{cite web
 |title=Interaction model – Probing space weather with comets
 |url=http://www.kvi.nl/~bodewits
 |archive-url=https://web.archive.org/web/20060213232726/http://www.kvi.nl/~bodewits
 |archive-date=2006-02-13
 |publisher=KVI atomics physics
 |access-date=2009-04-26
}}</ref>