The Bulletin of The Korean Astronomical Society (천문학회보)

The Korean Astronomical Society (한국천문학회)
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The ice features of Very Low Luminosity Objects (VeLLOs): Unveiling their episodic accretion history through the spectroscopic observation of AKARI IRC

  • Kim, Jaeyeong (School of Space Research, Kyung Hee University) ;
  • Lee, Jeong-Eun (School of Space Research, Kyung Hee University) ;
  • Aikawa, Yuri (Department of Astronomy, Graduate School of Science, The University of Tokyo) ;
  • Kim, Il-Seok (SE Lab) ;
  • Lee, Ho-Gyu (Korea Astronomy and Space Science Institute) ;
  • Jeong, Woong-Seob (Korea Astronomy and Space Science Institute) ;
  • Noble, Jennifer A. (Laboratoire de Physique des Lasers, Atomes et Molecules, The University de Lille)
  • Published : 2018.05.08
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Abstract

Although mass accretion from the disk to the central protostar is a key process of low mass star formation, the accretion mechanism is still poorly understood. To investigate "episodic accretion", which has been suggested as an accretion mechanism in low mass star formation, we have carried out near-infrared spectroscopic observations of three very low-luminosity objects (VeLLOs) and one background source, using InfraRed Camera onboard the AKARI space telescope. The ice absorption features of $H_2O$, $CO_2$, and CO were detected around the wavelengths of 3.0, 4.26, and $4.67{\mu}m$, respectively. In addition, we revealed the XCN ice feature, which is attributed to high energy UV photons produced by the episodic burst accretion. The comparisons of the ice abundances of our targets with those of other YSOs observed previously with AKARI IRC imply that the three VeLLOs had experienced burst accretions although they are now in a very quiescent phase.

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