2020A&A...637A..82D


Query : 2020A&A...637A..82D

2020A&A...637A..82D - Astronomy and Astrophysics, volume 637A, 82-82 (2020/5-1)

Mechanochemical synthesis of aromatic infrared band carriers. The top-down chemistry of interstellar carbonaceous dust grain analogues.

DARTOIS E., CHARON E., ENGRAND C., PINO T. and SANDT C.

Abstract (from CDS):


Context. Interstellar space hosts nanometre- to micron-sized dust grains, which are responsible for the reddening of stars in the visible. The carbonaceous-rich component of these grain populations emits in infrared bands that have been observed remotely for decades with telescopes and satellites. They are a key ingredient of Galactic radiative transfer models and astrochemical dust evolution. However, except for C60 and its cation, the precise carriers for most of these bands are still unknown and not well reproduced in the laboratory.
Aims. In this work, we aim to show the high-energy mechanochemical synthesis of disordered aromatic and aliphatic analogues provides interstellar relevant dust particles.
Methods. The mechanochemical milling of carbon-based solids under a hydrogen atmosphere produces particles with a pertinent spectroscopic match to astrophysical observations of aromatic infrared band (AIB) emission, linked to the so-called astrophysical polycyclic aromatic hydrocarbon hypothesis. The H/C ratio for the analogues that best reproduce these astronomical infrared observations lies in the 5±2% range, potentially setting a constraint on astrophysical models. This value happens to be much lower than diffuse interstellar hydrogenated amorphous carbons, another Galactic dust grain component observed in absorption, and it most probably provides a constraint on the hydrogenation degree of the most aromatic carbonaceous dust grain carriers. A broad band, observed in AIBs, evolving in the 1350-1200cm–1 (7.4-8.3µm) range is correlated to the hydrogen content, and thus the structural evolution in the analogues produced.
Results. Our results demonstrate that the mechanochemical process, which does not take place in space, can be seen as an experimental reactor to stimulate very local energetic chemical reactions. It introduces bond disorder and hydrogen chemical attachment on the produced defects, with a net effect similar to the interstellar space very localised chemical reactions with solids. From the vantage point of astrophysics, these laboratory interstellar dust analogues will be used to predict dust grain evolution under simulated interstellar conditions, including harsh radiative environments. Such interstellar analogues offer an opportunity to derive a global view on the cycling of matter in other star forming systems.

Abstract Copyright: © E. Dartois et al. 2020

Journal keyword(s): astrochemistry - dust, extinction - ISM: lines and bands - planetary nebulae: general - infrared: ISM

Simbad objects: 19

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Number of rows : 19
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 IRAS F00183-7111 Sy2 00 20 34.7 -70 55 27     20.6     ~ 129 0
2 OGLE SMC-LPV-4910 pA* 00 44 41.1035011488 -73 21 36.123508332   17.06 15.61 15.44 14.515 G:I 22 0
3 IRAS 04296+3429 pA* 04 32 56.9743899192 +34 36 12.459816288   16.13 14.09 13.64 11.64 G0Ia 140 0
4 IRAS 05073-6752 pA* 05 07 13.9164887208 -67 48 46.719455724           ~ 15 0
5 IRAS 05110-6616 pA* 05 11 10.6392128544 -66 12 53.624892600 20.528 18.416 16.629 15.70 14.536 F0Ib 19 0
6 IRAS S05211-6926 pA* 05 20 43.8870629914 -69 23 41.139112840 17.618 16.515 15.075 13.92 13.887 F5Ib(e) 21 0
7 IRAS Z05259-7052 pA* 05 25 20.7706707096 -70 50 07.476379728 17.562 16.570 15.335 14.480 16.252 A2Ib 14 0
8 IRAS 05289-6617 C* 05 29 02.412 -66 15 27.77   22.276 21.353     C 25 0
9 IRAS 05341+0852 pA* 05 36 55.0511076432 +08 54 08.656315452   15.37 13.45 12.95 11.43 F6I 111 0
10 IRAS 06111-7023 * 06 10 32.0148170760 -70 24 40.784730372           ~ 8 0
11 NAME IRAS F08572+3915 NW LIN 09 00 25.364 +39 03 54.23     16.66     ~ 400 1
12 NGC 4355 Sy2 12 26 54.6206739120 -00 52 39.421212996   14.21 13.37     ~ 460 2
13 IRAS 13416-6243 pA* 13 45 07.2573421656 -62 58 16.835990124           G1I 43 0
14 IRAS 15038-5533 MIR 15 07 34.776 -55 44 50.80           ~ 6 0
15 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 4006 3
16 IRAS 20000+3239 LP* 20 01 59.5133268456 +32 47 32.799122916   16.13 13.39 11.80 10.32 ~ 76 0
17 V* V1610 Cyg pA* 21 02 18.27 +36 41 37.0           F5Iae 859 1
18 HD 235858 pA* 22 29 10.3748806056 +54 51 06.344572284   11.40 9.52 8.47 7.34 G5Ia 245 0
19 IRAS 23304+6147 pA* 23 32 44.7858431592 +62 03 49.090372272   15.36 12.99 12.23 10.50 G2Ia 111 0

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2022.12.02-05:33:41

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