Protostars and Planets VI, Heidelberg, July 15-20, 2013

Poster 1B056

Observation of Massive Star Forming Regions at 30 Microns

Uchiyama, Mizuho (Institute of Astronomy, the University of Tokyo)
Miyata, Takashi (Institute of Astronomy, the University of Tokyo)
Sako, Shigeyuki (Institute of Astronomy, the University of Tokyo)
Kamizuka, Takafumi (Institute of Astronomy, the University of Tokyo)
Asano, Kentaro (Institute of Astronomy, the University of Tokyo)
Okada, Kazushi (Institute of Astronomy, the University of Tokyo)
Nakamura, Tomohiko (Department of Astronomy, the University of Tokyo)
Yamashita, Takuya (National Astronomical Observatory of Japan)
Fujiyoshi, Takuya (Subaru Telescope, National Astronomical Observatory of Japan)
Yoshii, Yuzuru (Institute of Astronomy, the University of Tokyo)

Formation of massive stars remains an open question in modern astronomy. How to prevent a massive molecular core from fragmenting into low-mass cores before it grows up to massive young stellar objects (MYSOs) is an important issue. A recent model predicts that a massive core grows up to a MYSO if it is heated by accreting radiation from less massive stars formed previously around the core(accretion-luminosity feedback model). To evaluate this model, it is important to observe interactions between objects in massive star forming regions with high spatial resolution because these regions exist far from us and are crowded. MYSOs are heavily obscured and their radiation is mainly emitted in the mid to far infrared wavelength. Therefore, the mid to far infrared observations are important to measure total fluxes and estimate luminosity and mass accurately.We have been carrying out mid-infrared survey observations of nearby massive star forming regions at 31 and 37 microns with the University of Tokyo Atacama 1.0-m Telescope with the mid-infrared camera MAX38. The MAX38 achieves high spatial resolutions of 8 arcsec at 31 micron which is better than that of any other space telescopes. We have observed three massive star forming regions and successfully obtained the first resolved images at 31 and 37 microns.We have found that each region consists of two components; an ultra compact HII region (UCHII) and a MYSO. We also have found that the masses of the MYSOs are larger than those of the UCHIIs in any observed regions. These suggest that the less massive objects began to collapse earlier because more massive objects evolved faster and UCHIIs are in the later evolutional stage than MYSOs. If the accretion-luminosity feedback works well, the less massive objects begin to collapse earlier. This corresponds to the results of our observations. Therefore, our results supports that the accretion-luminosity feedback works efficiently in the massive star forming regions.

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