INVESTIGATION OF CARBONACEOUS INTERSTELLAR DUST ANALOGUES BY INFRARED SPECTROSCOPY: EFFECTS OF ENERGETIC PROCESSING

Matﾎ, Belﾎn

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https://hdl.handle.net/2142/79334 Copy

Description

Title

INVESTIGATION OF CARBONACEOUS INTERSTELLAR DUST ANALOGUES BY INFRARED SPECTROSCOPY: EFFECTS OF ENERGETIC PROCESSING

Author(s)

Matﾎ, Belﾎn

Contributor(s)

• Herrero, Victor Jose
• Tanarro, Isabel
• Jimﾎnez-Redondo, Miguel

Issue Date

25-Jun-15

Keyword(s)

Astronomy

Abstract

Carbonaceous compounds, both solids and gas-phase molecules, are found in very diverse astronomical mediafootnote{A.G.G.M. Tielens. Rev. Mod. Phys., 85, 1021 (2013)}. A significant amount of the elemental carbon is found in small dust grains. This carbonaceous dust, mostly formed in the last stages of evolution of C-rich stars, is the carrier of characteristic IR absorption bands revealing the presence of aliphatic, aromatic and olefinic functional groups in variable proportionsfootnote{J.E. Chiar, A.G.G.M. Tielens, A.J. Adamson and A. Ricca. Astrophys. J., 770, 78 (2013)}. Among the various candidate materials investigated as possible carriers of these bands, hydrogenated amorphous carbon (a-C:H) has led to the best agreement with the observations. Carbonaceous grains are processed by H atoms, UV radiation, cosmic rays and interstellar shocks in their passage from asymptotic giant branch stars to planetary nebulae and to the diffuse interstellar medium. The mechanisms of a-C:H production and evolution in astronomical media are presently a subject of intensive investigation. In this work we present a study of the stability of carbonaceous dust analogues generated in chem{He}+chem{CH_4} radiofrequency discharges. In order to simulate the processing of dust in the interstellar environments, the samples have been subjected to electron bombardment, UV irradiation, and both chem{He} and chem{H_2} plasma processing. IR spectroscopy is employed to monitor the changes in the structure and composition of the carbonaceous films.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

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http://hdl.handle.net/2142/79334

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