FUV observations of the inner coma of 46P/Wirtanen

John W. Noonan, Walter M. Harris, Steven Bromley, Davide Farnocchia, Jian Yang Li, Kathleen E. Mandt, Joel Wm Parker, Kumar Venkataramani, Dennis Bodewits

Research output: Contribution to journalArticlepeer-review

6 Scopus citations


Far-ultraviolet observations of comets yield information about the energetic processes that dissociate the sublimated gases from their primitive surfaces. Understanding which emission processes are dominant, their effects on the observed cometary spectrum, and how to properly invert the spectrum back to the composition of the presumably pristine surface ices of a comet nuclei are all critical components for proper interpretation and analysis of comets. The close approach of comet 46P/Wirtanen in 2018-2019 provided a unique opportunity to study the innermost parts of a cometary coma with the Hubble Space Telescope Cosmic Origins Spectrograph, rarely accessible with remote observations, at length scales (hundreds of kilometers) and wavelengths (900-1430 Å) previously probed only by the European Space Agency's Rosetta spacecraft. Our observations show a complex picture for the inner coma; atomic production rates for H and O that show water is the dominant source of both, an abundance of atomic sulfur that is difficult to explain with the lifetimes of common sulfur parent molecules, and a density distribution that is poorly fit with both Haser and vectorial models.

Original languageEnglish (US)
Article number8
JournalPlanetary Science Journal
Issue number1
StatePublished - Feb 2021

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science
  • Geophysics


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