Editing Coma (comet) (section)

==Composition==
[[File:PIA20119-CometChristensen-C2006W3-CO2-WISE-20100420.jpg|thumb|right|C/2006 W3 (Christensen) – emitting carbon gas (infrared image)]]
The Rosetta mission found carbon monoxide, carbon dioxide, ammonia, methane and methanol in the Coma of Comet 67P, as well as small amounts of formaldehyde, hydrogen sulfide, hydrogen cyanide, sulfur dioxide and carbon disulfide.<ref name="cnet">{{cite web|url=http://www.cnet.com/news/the-scent-of-a-comet-rotten-eggs-and-pee/|publisher=cnet.com|title=The scent of a comet: Rotten eggs and pee – CNET|access-date=2017-01-08}}</ref>

The four top gases in 67P's halo were water, carbon dioxide, carbon monoxide, and oxygen.<ref name="phys.org">{{cite web|url=http://phys.org/news/2015-10-rosetta-molecular-oxygen-comet-67p.html|publisher=phys.org|title=Rosetta finds molecular oxygen on comet 67P (Update)|access-date=2017-01-08}}</ref> The ratio of oxygen to water coming off the comet remained constant for several months.<ref name="phys.org"/>