AKARI NIR spectroscopy of interstellar ices

Takashi Onaka, Tamami I. Mori, Itsuki Sakon, Fumihiko Usui, Ronin Wu, Takashi Shimonishi

Research output: Contribution to journalArticlepeer-review


The Infrared Camera (IRC) onboard AKARI has a near-infrared (2-5μm) spectroscopic capability with high sensitivity that allows us to study the major ice components in various objects. In particular, H2O and CO2 ice absorption features have been detected towards nearby galaxies, including several young stellar objects (YSOs) in the Large Magellanic Cloud (LMC), as well as a number of HII region-PDR complexes for the first time by IRC spectroscopy. While observations in the LMC show a high ratio (~0.34) of the CO2 to H2O ice column densities, the ratios in Galactic HII-region-PDR complexes are in the range of 0.1-0.2, being compatible with those found in Galactic massive YSOs in previous studies. The good correlation supports concurrent formation of the two ice species on the grain surface and the higher ratio in the low-metallicity LMC suggests possible environmental effects in the formation process.

Original languageEnglish
Pages (from-to)319-320
Number of pages2
JournalProceedings of the International Astronomical Union
Issue numberA29A
Publication statusPublished - 2015


  • (ISM:) dust
  • ISM: lines and bands
  • astrochemistry
  • extinction
  • infrared: ISM

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Astronomy and Astrophysics
  • Nutrition and Dietetics
  • Public Health, Environmental and Occupational Health
  • Space and Planetary Science


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