Polarimetric studies on Interstellar grains
Grant-in-Aid for international Scientific Research
|Allocation Type||Single-year Grants|
|Research Institution||Nagoya University|
SATO Shuji Nagoya University, Professor, 大学院・理学研究科, 教授 (50025483)
JONES T.J. ミネソタ大学, 教授
WOODWARD C.E ワイオミング大学, 助教授
TAMURA Motohide National Astonomical Observatory, Research Associate, 光学赤外線天文学研究系, 助手 (00260018)
KATAZA Hirokazu University of Tokyo, Research Associate, 天文教育研究センター, 助手 (70242097)
NAGATA Tetsuya Nagoya University, Associate Professor, 大学院・理学研究科, 助教授 (80208016)
WOODWARD Charles E University of Wyoming, Associate Professor
JONES Terry J University of Minnesota, Professor
|Project Period (FY)
1995 – 1996
Completed(Fiscal Year 1996)
|Budget Amount *help
¥7,200,000 (Direct Cost : ¥7,200,000)
Fiscal Year 1996 : ¥3,600,000 (Direct Cost : ¥3,600,000)
Fiscal Year 1995 : ¥3,600,000 (Direct Cost : ¥3,600,000)
|Keywords||interstellar extinction / interstellar polarization / star-forming region|
Spectroscopy and spectro-polarimetry have been made for reddened giants and supergiants in the Galactic plane, young stellar objects dark clouds, and back ground stars of dark clouds. Reddened stars in the Galactic plane is from an I-band objective prism survey, and most of them have turned out to be moderately reddened M-type stars that are intrinsically red. Their extinction and polarization agree fairly well with the relationship in the literature ; this suggests that even in dark clouds grains produce extinction and polarization in the same manner as in diffuse clouds. From their observations, we demonstrate that some of them show deep absorption at 3.4 microns, and that the 3.4 micron absorption feature increases with the interstellar extinction.
One objects show a polarization excess in the ice band at 3.0 microns. This objects would be a useful tool when studying the ice properties because it is located behind a dark cloud and free from scattering effect. Spectro-polarimetry of many young stellar objects in dark clouds are also made in the ice band. The grain alignment efficiency have been compared with a model calculation, and usual magnetic field seems to be sufficient for the alignment. On the other hand, the spectral shape of the absorption and polarization is difficult to be reproduced by laboratory analogs of the interstellar ice.
A number of objects with the ice band absorption and the 3.3 micron emission feature have been found in star forming regions. Some of them require further observations of higher spatial resolution.
Research Output (10results)