Upper Limits for Emissions in the Coma of Comet 67P/Churyumov-Gerasimenko Near Perihelion as Measured by Rosetta's Alice Far-Ultraviolet Spectrograph

Abstract

The Alice far-UV imaging spectrograph (700-2050 A) acquired over 70,000 spectral images during Rosetta's 2-year escort mission, including over 20,000 in the months surrounding perihelion when the comet activity level was highest. We have developed automated software to fit and remove ubiquitous H, O, C, S, and CO emissions from Alice spectra, along with reflected solar continuum and absorption from gaseous H2O in the comet's coma, which we apply to a "grand sum" of integrations taken near perihelion. We present upper limits on the presence of one ion and 17 neutral atomic species for this time period. These limits are compared to results obtained by other Rosetta instruments where possible, as well as to CI carbonaceous chondrites and solar photospheric abundances.

9 pages, 3 figures; Astronomical Journal, in press

References in corpus (4)

• Alice: The Rosetta Ultraviolet Imaging Spectrograph
• Evolution of CO${}_2$, CH${}_4$, and OCS abundances relative to H${}_2$O in the coma of comet 67P around perihelion from Rosetta/VIRTIS-H observations
• The Fourth Positive System of Carbon Monoxide in the Hubble Space Telescope Spectra of Comets
• Stellar Occultation by Comet 67P/Churyumov-Gerasimenko Observed with Rosetta's Alice Far-Ultraviolet Spectrograph