AKARI NEAR-INFRARED SPECTROSCOPY: DETECTION OF H2O AND CO2 ICES TOWARD YOUNG STELLAR OBJECTS IN THE LARGE MAGELLANIC CLOUD

作者：Shimonishi Takashi; Onaka Takashi; Kato Daisuke; Sakon Itsuki; Ita Yoshifusa; Kawamura Akiko; Kaneda Hidehiro

来源：Astrophysical Journal Letters, 2008, 686(2): L99-L102.

DOI：10.1086/592948

• circumstellar matter
• dust, extinction
• ISM: abundances
• ISM: molecules
• Magellanic Clouds
• stars: pre-main-sequence

We present the first results of AKARI Infrared Camera near-infrared spectroscopic survey of the Large Magellanic Cloud (LMC). We detected absorption features of the H2O ice 3.05 mu m and the CO2 ice 4.27 mu m stretching mode toward seven massive young stellar objects (YSOs). These samples are for the first time spectroscopically confirmed to be YSOs. We used a curve-of-growth method to evaluate the column densities of the ices and derived the CO2/H2O ratio to be 0.45 +/- 0.17. This is clearly higher than that seen in Galactic massive YSOs (0.17 +/- 0.03). We suggest that the strong ultraviolet radiation field and/or the high dust temperature in the LMC may be responsible for the observed high CO2 ice abundance.

• 出版日期2008-10-20
• 单位中国科学院国家天文台