Grain properties of Oort cloud comets: Modeling the mineralogical composition of cometary dust from mid-infrared emission features

Takafumi Ootsubo, Jun ichi Watanabe, Hideyo Kawakita, Mitsuhiko Honda, Reiko Furusho

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

We carried out spectroscopic observations (R ∼ 250) of Oort cloud comet C/2001 Q4 (NEAT) at the post-perihelion (rh = 1.02 AU, Δ = 0.93 AU, 2004 June 4.2 UT) in mid-infrared 8 - 13 μ m region using the Cooled Mid-Infrared Camera and Spectrometer (COMICS) on 8.2 m Subaru Telescope. The silicate feature of comet Q4 shows the crystalline olivine peak at 11.2 μ m along with the broad amorphous silicate features. We present the detailed results of our fitting analysis by using a thermal emission model of cometary coma grains, and compare with other results of C/2001 Q4 (NEAT) at the different heliocentric distance pre-perihelion (rh = 0.97 AU), comet C/2002 V1 (NEAT), and comet C/1995 O1 (Hale-Bopp). The mass ratios of crystalline to amorphous silicate in sub-μ m grain size are between 1.9 and 2.5 for these comets. The similarity of coma dust mineralogy among these Oort cloud comets implies that the dust grains in these comets represent the similar physical conditions in the solar nebula and potentially similar regions of icy planetesimal formation.

Original languageEnglish
Pages (from-to)1044-1049
Number of pages6
JournalPlanetary and Space Science
Volume55
Issue number9
DOIs
Publication statusPublished - 2007 Jun 1

Keywords

  • Comets
  • Dust
  • Infrared
  • Silicate

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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