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

Brian A. Keeney (1) , S. Alan Stern (1) , Ronald J. Vervack, Jr (2) , Matthew M. Knight (3) , John Noonan (4) , Joel Wm. Parker (1) , Michael F. A'Hearn (3) , Jean-Loup Bertaux (5) , Lori M. Feaga (3) , Paul D. Feldman (6) , Richard A. Medina (1) , Jon P. Pineau (7) , Rebecca N. Schindhelm (8, 1) , Andrew J. Steffl (1) , M. Versteeg (9) , Harold A. Weaver (2)

1 Department of Space Studies [Boulder]
2 APL - Johns Hopkins University Applied Physics Laboratory [Laurel, MD]
3 Department of Astronomy [College Park]
4 LPL - Lunar and Planetary Laboratory [Tucson]
5 PLANETO - LATMOS
6 Department of Physics and Astronomy [Baltimore]
7 Stellar Solutions, inc.
8 Ball Aerospace and Technology Corp.
9 SwRI - Southwest Research Institute [San Antonio]

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.

Domains: Sciences of the Universe [physics]

Brian A. Keeney, S. Alan Stern, Ronald J. Vervack, Jr, Matthew M. Knight, John Noonan, et al.. Upper Limits for Emissions in the Coma of Comet 67P/Churyumov–Gerasimenko near Perihelion as Measured by Rosetta's Alice Far-UV Spectrograph. The Astronomical Journal, 2019, 158 (6), art. 252 (9p.). ⟨10.3847/1538-3881/ab552e⟩. ⟨insu-02362729⟩