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Emission Mechanism of Carbonaceous Interstellar and Circumstellar Dusts

Research Project

Project/Area Number 01540217
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field Astronomy
Research InstitutionThe University of ElectroーCommunications

Principal Investigator

SAKATA Akira  電気通信大学, 電気通信学部, 助手 (90017393)

Co-Investigator(Kenkyū-buntansha) WADA Setsuko  電気通信大学, 電気通信学部, 助手 (30017404)
Project Period (FY) 1989 – 1990
Project Status Completed (Fiscal Year 1990)
Budget Amount *help
¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1990: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1989: ¥500,000 (Direct Cost: ¥500,000)
Keywordsreflection nebula, / carbonaceous dust, / emission spectrum, / visual light / fluorescence, / interstellar dust / infrared / 輻射スペクトル / 赤外スペクトル / 赤外線発光 / 炭素質物質 / 惑星状星雲 / 星周塵
Research Abstract

We have shown in a previous paper that oxidized f-QCC (Filmy Quenched Carbonaceous Composite) has absorption features that correspond to that of the interstellar 3.3, 3.4, 6.2, 7.7, 8.6, and 11.3mum mnission features. Here we present new laboratory data showing that oxidized f-QCC, after heating to 500^゚C, has a 3.29 mum absorption feature that matches precisely the wavelength of the 3.29mum interstellar emission feature. In addition, the width of the fーQCC feature is close to that of the 3.29mum emission feature observed in NGC 7027, Orion, and IRAS 21282+5050. Laboratory spectra of polycyclic hydrocarbons (PAHs) were also obtained, and comparison of the fーQCC and PAH absorption opectra to that of the 3.29mum emission feature indicates the fーQCC provides much better match. We therefore suggest that fーQCC is representative of the class of material giving rise to the emission features in the interstellar medium.
A red excess emission were observed in 12 objects among 24 reflection nebula by Witt and Boroson (1990). The emission spectra were single broad features peaked at 650-700nm with about 130nm of FWHM. Witt and Boroson attributed them to the fluorescence of hydrogenated amorphous carbon dusts. We collected QCCs on a substrate at a temperature lower than room temperature. The QCCs were mixture of low molecular weight chemical species such as molecules and radicals. They emit fluorescence under UV irradiation. The spectra of fluorescence of QCCs agreed well to the observed red excess emissions.
In order to analyze an IR spectrum of interstellar and circumstellar dust, it is necessary to measure an emission spectrum of a candidate dust material. We examined a simple method for IR emission measurement using a sample compartment emission accessory, made by Connecticut Instrument U.S.A. We achieved a test measurement with the accessory, and obtained a preliminary result.

Report

(3 results)
  • 1990 Annual Research Report   Final Research Report Summary
  • 1989 Annual Research Report

Research Products

(8 results)

All Other

All Publications (8 results)

  • [Publications] A.Sakata, S.Wada, T.Onaka,and A.T.Tokunaga: "Quenched Carbonaceous Composite(QCC):III.Comparison to the 3.29 Micron Interstellar Emission Feature" Astrophysical Journal. 353. 543-548 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1990 Final Research Report Summary
  • [Publications] A. Sakata, S. Wada, T. Onaka, and TOKUNAGA, A. T.: "Quenched Carbonaceous Composite (QCC) : III. Comparison to the 3.29 Micron Interstellar Emission Feature" Astrophysical Journal,. 353. 543-548 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1990 Final Research Report Summary
  • [Publications] A.Sakata,S.Wada,T.Onaka,and A.T.Tokunaga: "Quenched Carbonaceous Composite(QCC):III.Comparison to the 3.29 Micron Interstellar Emission Feature" Astrophysical Journal. 353. 543-548 (1990)

    • Related Report
      1990 Annual Research Report
  • [Publications] A.Sakata,S,Wada,T.Onaka,A.T.Tokunaga:"Quenched Carbonaceous Composite(QCC):III.Comparison to the 3.29Micron Interstellar Emission Feature" Astrophys.J.,. (1990)

    • Related Report
      1989 Annual Research Report
  • [Publications] A.Sakata,S.Wada,T.Onaka,and A.T.Tokunaga:"Quenched Carbonaceous Composite(QCC):Thermal Alteration of QCC and PAHs," "Dusty Objects in the Universe",ed.E.Bussoletti,(Kluwer Academic Publishers). (1990)

    • Related Report
      1989 Annual Research Report
  • [Publications] A.Sakata,S.Wada:"Chemical,Optical and Infrared Properties of QCCs," "Interstellar Dust",IAU#135 Symp.,ed.L.Allamandola and A.G.G.M.Tielens,(Reidel Dordrecht),. 191-196 (1989)

    • Related Report
      1989 Annual Research Report
  • [Publications] 坂田朗,和田節子: "宇宙の炭素-その生成、発展-" 炭素. 1989. 150-160 (1989)

    • Related Report
      1989 Annual Research Report
  • [Publications] 坂田朗,和田節子: "炭素質の塵の観測とその合成実験" 天文月報. 82巻. 84-89 (1989)

    • Related Report
      1989 Annual Research Report

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Published: 1989-03-31   Modified: 2016-04-21  

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