Investigation on the physical structure of protostellar disks with observations at millimeter and submillimeter wavelengths

2006 Fiscal Year Final Research Report Summary

• Project/Area Number: 16540210
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Astronomy
• Research Institution: Ibaraki University
• Principal Investigator: MOMOSE Munetake Ibaraki University, College of Sciences, Associate Professor, 理学部, 助教授 (10323205)
• Project Period (FY): 2004 – 2006
• Keywords: Star Formation / Protoplanetary disk / Radio Astronomy / Submillimeter

Research Abstract

The purpose of this study is to reveal in detail the circumstellar environment of protostars and physical structure of protoplanetary disks with observations at millimeter and submillimeter wavelengths. The highlights of this study are the followings ; (1) CO (J=1-0) and (J=3-2) observations toward HD163296, a pre-main sequence star with its mass of twice the solar mass, with the Nobeyama 45m telescope and the ASTE submillimeter telescope. Simultaneous fitting of the obtained line profiles of these two lines has revealed that the mass fraction of the CO molecule relative to dust particles can be significantly lower than that for the interstellar medium and that the CO excitation temperature can be higher than expected from the previous observations of dust continuum emissions. These results are consistent with theoretical prediction in which gas components of protoplanetary disks are dispersed via photo-dissociation. We reported these results in the annual meeting of the Astronomical S ociety of Japan in March 2007. (2) We made CO(J=3-2) observations toward 11 classical T Tauri stars in Taurus molecular cloud with the ASTE telescope, and found the integrated intensity of the enhanced emission toward the star shows fairly good correlation with the H-alpha luminosity, which is a good measure of accretion activity of circumstellar disk. This suggests the disk accretion activity diminishes as the amount of dense circumstellar material in the central regions within 20", or 2800 AU from the central star, decreases. We reported these results in the Conference "Science with the ALMA : a new era if Astrophysics", which was held in November 2006 in Madrid, Spain. (3) SiO (J=8-7) observations of the protostar candidate HH212 IRS revealed prominent emission features associated with the outflows. Its distribution shows excellent spatial correlation with the H2 emission at near infrared wavelengths. The results have already been published in "Publications of Astronomical Society of Japan", volume 53.

Research Products

• [Journal Article] Kinematics of SiO J= 8-7 Emission towards the HH 212 Jet (2006)
  • Author(s): Takami, S., Takakuwa, S., Momose, M., Hayashi, M., Davis, C.J., Pyo, T.-S., Nishikawa, T., Kohno, K.
  • Journal Title: Publications of the Astronomical Society of Japan 53 Pages: 563-568
  • Description: 「研究成果報告書概要(和文)」より