Evidence of icy grains in comet C/2002 T7 (LINEAR) at 3.52 AU

Hideyo Kawakita, Jun Ichi Watanabe, Takafumi Ootsubo, Ryosuke Nakamura, Tetsuharu Fuse, Naruhisa Takato, Sho Sasaki, Takanori Sasaki

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37 Citations (Scopus)

Abstract

We present evidence of icy grains in the coma of comet C/2002 T7 (LINEAR) at 3.52 AU from the Sun. This comet will approach the Sun in the spring of 2004, and it is expected to be very bright near its perihelion passage. The comet was observed using the Subaru Telescope with the Cooled Infrared Spectrograph and Camera for OHS (CISCO) on 2003 September 14.6 (UT). The near-infrared (J, H, K) spectrum was extracted from the near-nucleus region (1250 km × 1250 km at the comet), and it showed clear absorption features at 1.5 and 2.05 μm that originated from water ice grains. The calculated reflectance spectrum, based on the intimate mixture model for water ice grains and astronomical silicate grains (the diameters are 5 and 0.5 μm, respectively), can reproduce the observed reflectance spectrum of the comet up to 2.1 μm. The poor fit for the wavelength region longer than 2.1 μm is probably indicative of other grain species to be included in the model. Furthermore, the absence of the 1.65 μm feature of crystalline water ice may indicate that the water ice was in an amorphous state during the observation.

Original languageEnglish
Pages (from-to)L191-L194
JournalAstrophysical Journal
Volume601
Issue number2 II
Publication statusPublished - 2004 Feb 1

Keywords

  • Comets: general
  • Comets: individual (C/2002 T7 (LINEAR))
  • Solar system: formation

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Kawakita, H., Watanabe, J. I., Ootsubo, T., Nakamura, R., Fuse, T., Takato, N., Sasaki, S., & Sasaki, T. (2004). Evidence of icy grains in comet C/2002 T7 (LINEAR) at 3.52 AU. Astrophysical Journal, 601(2 II), L191-L194.