Deep Impact has taken an early look at some of the chemicals in the coma of Comet Tempel 1, detecting water, carbon dioxide, carbon monoxide, and hydrocarbons via spectral analysis. The coma is an envelope of gas and dust that becomes more active as a comet approaches the Sun. Outbursts of material occur as the comet heats up, though the exact mechanism is not well understood. Deep Impact also captured images with its medium-resolution camera of on outburst on June 23, 2005.
Scientists hope tomorrow’s impact between Deep Impact’s impactor spacecraft and Comet Tempel 1 will provide an even more detailed look at the comet’s composition by allowing pristine material inside to be uncovered. The impact is scheduled to occur at 10:52 p.m. Pacific Daylight Time. NASA TV will provide coverage of the event and Space.com has posted a list of webcasts to be provided by various observatories.