2004A&A...415..425V


C.D.S. - SIMBAD4 rel 1.7 - 2019.12.10CET11:11:11

2004A&A...415..425V - Astronomy and Astrophysics, volume 415, 425-436 (2004/2-4)

A quantitative analysis of OCN formation in interstellar ice analogs.

VAN BROEKHUIZEN F.A., KEANE J.V. and SCHUTTE W.A.

Abstract (from CDS):

The 4.62µm absorption band, observed along the line-of-sight towards various young stellar objects, is generally used as a qualitative indicator for energetic processing of interstellar ice mantles. This interpretation is based on the excellent fit with OCN, which is readily formed by ultraviolet (UV) or ion-irradiation of ices containing H2O, CO and NH3. However, the assignment requires both qualitative and quantitative agreement in terms of the efficiency of formation as well as the formation of additional products. Here, we present the first quantitative results on the efficiency of laboratory formation of OCN from ices composed of different combinations of H2O, CO, CH3OH, HNCO and NH3 by UV- and thermally-mediated solid state chemistry. Our results show large implications for the use of the 4.62µm feature as a diagnostic for energetic ice-processing. UV-mediated formation of OCN from H2O/CO/NH3 ice matrices falls short in reproducing the highest observed interstellar abundances. In this case, at most 2.7% OCN is formed with respect to H2O under conditions that no longer apply to a molecular cloud environment. On the other hand, photoprocessing and in particular thermal processing of solid HNCO in the presence of NH3 are very efficient OCN formation mechanisms, converting 60%-85% and ∼100%, respectively of the original HNCO. We propose that OCN is most likely formed thermally from HNCO given the ease and efficiency of this mechanism. Upper limits on solid HNCO and the inferred interstellar ice temperatures are in agreement with this scenario.

Abstract Copyright:

Journal keyword(s): methods: laboratory - ISM: molecules - ISM: lines and bands

CDS comments: Table 5 : AFGL 961E part of AFGL 961.

Simbad objects: 24

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Number of rows : 24

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 NAME W3 IRS 5 Y*O 02 25 40.54 +62 05 51.4           B1 322 0
2 HBC 393 FU* 04 31 34.077 +18 08 04.90           K3V/M3III 775 2
3 V* HL Tau TT* 04 31 38.437 +18 13 57.65   16.02 15.10 14.21   K5 1135 0
4 IRAS 04287+1807 mul 04 31 38.8 +18 13 57           ~ 796 0
5 Kim 1-38 * 04 39 38.8673861844 +26 11 26.630421918           K1III 124 0
6 IRAS 0437+257P08 TT? 04 39 55.7451364657 +25 45 01.943057594           B5 158 1
7 NAME Mon R2 IRS 2 * 06 07 45.83 -06 22 53.5           B0 98 0
8 RAFGL 961 Y*O 06 34 37.741 +04 12 44.20           ~ 233 1
9 IRAS 08448-4343 cor 08 46 33.8 -43 54 33           ~ 56 1
10 NGC 4945 Sy2 13 05 27.279 -49 28 04.44   9.31 14.40 7.55   ~ 1231 2
11 Elia 2-29 Y*O 16 27 09.43032 -24 37 18.7716           ~ 261 1
12 HBC 650 TT* 16 34 29.32 -15 47 01.4           K3.0 164 2
13 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 3293 3
14 GCIRS 19 * 17 45 41.087 -29 00 47.98           M4Ib 36 0
15 W 33a Y*O 18 14 39.0 -17 52 03           ~ 571 0
16 RAFGL 2136 SFR 18 22 26.8740 -13 30 17.177           ~ 233 0
17 RAFGL 7009S Y*O 18 34 20.911 -05 59 42.23           ~ 185 0
18 V* V710 CrA Or* 19 01 50.67792 -36 58 09.6132           K7: 114 0
19 RAFGL 2591 Y*O 20 29 25.2650 +40 11 26.532   18       ~ 561 5
20 V* PV Cep Or* 20 45 53.9537161790 +67 57 38.678052612   19.27 17.46 15.98 14.60 A5 249 3
21 V* V1735 Cyg FU* 21 47 20.6624829527 +47 32 03.856911703           ~ 149 0
22 SH 2-140 OpC 22 19 07.8 +63 17 07           ~ 630 2
23 IRAS 22176+6303 SFR 22 19 17.978 +63 18 52.92           ~ 588 0
24 [WBN74] NGC 7538 IRS 9 Y*O 23 14 01.63 +61 27 20.2           ~ 336 0

    Equat.    Gal    SGal    Ecl

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2019.12.10-11:11:11

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