| Project/Area Number |
60460010
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Astronomy
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| Research Institution | Kyoto University |
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Principal Investigator |
HASEGAWA Hiroichi Kyoto University Faculty of Science Professor, 理学部, 教授 (20025232)
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| Co-Investigator(Kenkyū-buntansha) |
FUJIWARA Akira Kyoto University Faculty of Science Instructor, 理学部, 助手 (70173482)
MAIHARA Toshinori Kyoto University Faculty of Science Associate Professor, 理学部, 助教授 (90025445)
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| Project Period (FY) |
1985 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥7,500,000 (Direct Cost: ¥7,500,000)
Fiscal Year 1986: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1985: ¥6,600,000 (Direct Cost: ¥6,600,000)
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| Keywords | Comet Halley / Infrared observation / Infrared spectroscopy / Interstellar solid grain / Interstellar gas / dust grain / ガス生成率 |
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| Research Abstract |
We have conducted infrared spectroscopic observations of Comet Halley by the use of a newly developed grating spectrometer attached to ground-based telescopes in Japan and in Australia.
Comets are intriguing objects that possess information on the condensation of protoplanetary material under physical and chemical environments of the primordial gas in the epoch of formation of the solar system. Therefore it is of particular importance to study the composition of comet nuclei. So we undertook infrared spectroscopic observation of Comet Halley to detect the so-called parent molecules supposedly comprising the inner cometary atmosphere.
During the first year we designed and built a compact grating spectrometer for the purpose of near-infrared spectrophotometry of Comet Halley. We exploited an 8-element InSb array detector in conjunction with cooled grating optics capable of making sensitive and efficient observations.
The actual observations were on Nov. 28, 1985, Jan. 3, 1986, and from Mar. 21 to 25, 1986. A merginal emission feature of CO has been obtained in the first series of observation, giving an upper limit of CO production rate of <10^(30)> <sec^(-1)> In the second series, an upper limit of <CH_4> production rate: 5 x <10^(29)> <sec^(-1)> has been obtained, suggesting its significantly lower abundance as a cometary constituent than expected. The consecutive spectrophotometric data during the third series of observation clearly indicates day-to-day variation with an apparent periodicity of continuum emission in the near-infrared, which poses an interesting problem concerning time variation of the dust producing activity directly associated to the nucleus rotation.
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