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Alice is a far-ultraviolet imaging spectrograph onboard Rosetta that, amongstmultiple objectives, is designed to observe emissions from various atomic andmolecular species from within the coma of comet 67P/Churyumov-Gerasimenko. Theinitial observations, made following orbit insertion in August 2014, showedemissions of atomic hydrogen and oxygen spatially localized close to thenucleus and attributed to photoelectron impact dissociation of H2O vapor.Weaker emissions from atomic carbon were subsequently detected and alsoattributed to electron impact dissociation, of CO2, the relative H I and C Iline intensities reflecting the variation of CO2 to H2O column abundance alongthe line-of-sight through the coma. Beginning in mid-April 2015, Alicesporadically observed a number of outbursts above the sunward limbcharacterized by sudden increases in the atomic emissions, particularly thesemi-forbidden O I 1356 multiplet, over a period of 10-30 minutes, without acorresponding enhancement in long wavelength solar reflected lightcharacteristic of dust production. A large increase in the brightness ratio O I1356/O I 1304 suggests O2 as the principal source of the additional gas. Theseoutbursts do not correlate with any of the visible images of outbursts takenwith either OSIRIS or the navigation camera. Beginning in June 2015 the natureof the Alice spectrum changed considerably with CO Fourth Positive bandemission observed continuously, varying with pointing but otherwise fairlyconstant in time. However, CO does not appear to be a major driver of any ofthe observed outbursts.

The Nature and Frequency of the Gas Outbursts in Comet 67P/Churyumov-Gerasimenko observed by the Alice Far-ultraviolet Spectrograph on Rosetta