The volatile composition and activity of comet 103P/Hartley 2 during the EPOXI closest approach

N. Dello Russo, R. J. Vervack, C. M. Lisse, H. A. Weaver, H. Kawakita, H. Kobayashi, A. L. Cochran, W. M. Harris, A. J. McKay, N. Biver, D. Bockelée-Morvan, J. Crovisier

Research output: Contribution to journalArticlepeer-review

46 Scopus citations

Abstract

We report time-resolved measurements of the absolute and relative abundances of eight parent volatiles (H2O, CH3OH, C 2H6, C2H2, NH3, HCN, H2CO, and HC3N) in the coma of 103P/Hartley 2 on UT 2010 November 4, the date the EPOXI spacecraft made its closest approach to the comet, using high-dispersion infrared spectroscopy with NIRSPEC at the W. M. Keck Observatory. Overall gas and dust production increased by roughly 60% between UT 10:49 and 15:54. Differences in the spatial distributions of species in the coma suggest icy sources of different composition in the nucleus of 103P/Hartley 2. However, differences in the relative abundances of species with time are minor, suggesting either internal compositional heterogeneity in 103P/Hartley 2 is small compared with the diversity of chemistry observed within the comet population, or more significant heterogeneity exists on scales smaller than our spatial resolution. Observations contemporaneous with the EPOXI encounter test how compositional heterogeneity over the surface and the inner coma of a comet manifests itself in remote-sensing observations of the bulk coma.

Original languageEnglish (US)
Article numberL8
JournalAstrophysical Journal Letters
Volume734
Issue number1 PART 2
DOIs
StatePublished - Jun 10 2011
Externally publishedYes

Keywords

  • astrochemistry
  • comets: general
  • comets: individual (103P/Hartley 2)
  • infrared: general
  • molecular data
  • techniques: spectroscopic

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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