Query : 2001A&A...378..597P

2001A&A...378..597P - Astronomy and Astrophysics, volume 378, 597-607 (2001/11-1)

The use of kerogen data in understanding the properties and evolution of interstellar carbonaceous dust.


Abstract (from CDS):

A number of authors have, in the past decade, pointed to the similarity of the 3.4-µm band of kerogen with that of the Galactic Centre (GC). Kerogen is a family of solid terrestrial sedimentary materials essentially made of C, H and O interlocked in a disordered, more or less aliphatic, structure. Here, the most recent results of the astronomical literature and the rich quantitative geochemical literature are tapped with two purposes in mind: extend the analogy to the mid-IR bands and, based on these new constraints, quantitatively assess the properties of the carrier dust. It is shown that the great diversity of IR astronomical IS (interstellar) dust is paralleled by the changes in kerogen spectra as the material spontaneously and continuously evolves (aromatizes) in the earth. Since the composition and structure of kerogen are known all along its evolution, it is possible, by spectral analogy, to estimate these properties for the corresponding astronomical carriers. The Galactic Centre 3.4µm feature is thus found to correspond to an early stage of evolution, for which the composition in C, H and O and the structure of the corresponding kerogen are known and reported here. The role of oxygen in the subsequent evolution and its contribution to different bands are stressed. The above provides new arguments in favour of the 3.4-µm band, as well as the observed accompanying mid-IR bands, being carried by kerogen-like dust born in CS (circumstellar) envelopes, mostly of AGB (asymptotic giant branch) objects. Subsequent dust evolution in composition and structure (aromatization) is fast enough that the unidentified infrared bands can already show up in well-developed planetary nebulae (PNe), as observed. A fraction of incompletely evolved dust can escape into the diffuse IS medium and molecular clouds. As a consequence, aliphatic and aromatic features can both be detected in the sky, in emission (Proto-PNe, PNe and PDRs (photo-dissociation regions)) as well as in absorption (dense molecular clouds and diffuse ISM). Changes in wavelength and band width with line of sight are explained by changes in the nature and number of chemical functional groups composing the carrier material. Predictions of the kerogen model in the UV and far IR are proposed for testing.

Abstract Copyright:

Journal keyword(s): carbonaceous dust - kerogen - galactic centre - interstellar medium-dust birth and evolution

CDS comments: fig5 IRAS 05341+0852 instead of 08341+0852

Simbad objects: 9

goto Full paper

goto View the references in ADS

Number of rows : 9
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 IRAS 04296+3429 pA* 04 32 56.9743899192 +34 36 12.459816288   16.13 14.09 13.64 11.64 G0Ia 140 0
2 RAFGL 618 pA* 04 42 53.6242032600 +36 06 53.400902220   16.32   12.59   C-rich 988 0
3 IRAS 05341+0852 pA* 05 36 55.0511076432 +08 54 08.656315452   15.37 13.45 12.95 11.43 F5I 111 0
4 NGC 2023 RNe 05 41 37.9 -02 15 52           ~ 614 1
5 HD 56126 pA* 07 16 10.2590823192 +09 59 47.954735376   9.20 8.32     F0/5Ia 312 0
6 V* V842 Cen No* 14 35 52.5683885352 -57 37 35.391092232           ~ 142 0
7 NAME Sgr A Region reg 17 45 12 -28 48.3           ~ 936 0
8 V* V1610 Cyg pA* 21 02 18.27 +36 41 37.0           F5Iae 863 1
9 HD 235858 pA* 22 29 10.3748806056 +54 51 06.344572284   11.40 9.52 8.47 7.34 G5Ia 245 0

To bookmark this query, right click on this link: simbad:objects in 2001A&A...378..597P and select 'bookmark this link' or equivalent in the popup menu


© Université de Strasbourg/CNRS

    • Contact