2010A&A...516A..98R


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.08CEST17:27:08

2010A&A...516A..98R - Astronomy and Astrophysics, volume 516, A98-98 (2010/6-3)

HNCO enhancement by shocks in the L1157 molecular outflow.

RODRIGUEZ-FERNANDEZ N.J., TAFALLA M., GUETH F. and BACHILLER R.

Abstract (from CDS):

The isocyanic acid (HNCO) has an extended distribution in the centers of the Milky Way and the spiral galaxy IC342. Based on both the morphology of the emission and the HNCO abundance with respect to H2, several authors hypothesized that HNCO could be a good tracer of interstellar shocks. We test this hypothesis by observing a well-known Galactic source whose chemistry is dominated by shocks. We observed several transitions of HNCO towards L1157-mm and two positions (B1 and B2) in the blue lobe of the molecular outflow. The HNCO line profiles exhibit the same characteristics as other well-known shock tracers such as CH3OH, H2CO, SO, or SO2. The three molecules HNCO, SO2, and OCS are the only ones detected so far whose emission is more intense in B2 than in B1, making these species valuable probes of chemical differences along the outflow. The HNCO abundance with respect to H2 is (0.4-1.8)x10–8 in B1 and (0.3-1)x10–7 in B2. These abundances are the highest ever measured, and imply an increment with respect to L1157-mm of up to a factor of 83, demonstrating that this molecule is a good shock tracer. we demonstrate that shocks can produce the HNCO abundance measured in galactic nuclei and even higher values. We propose that the gas phase abundance of HNCO is produced by both grain mantle erosion by the shock waves and by neutral-neutral reactions in gas phase involving CN and O2. The observed anticorrelation between CN and HNCO fluxes supports this scenario. The observed similarities between the HNCO emission and sulfur-bearing molecules may be caused by formation pathways that also involve O2.

Abstract Copyright:

Journal keyword(s): ISM: individual objects: L1157 - ISM: jets and outflows - ISM: molecules - stars: formation

Simbad objects: 13

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Number of rows : 13

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 W 3 MoC 02 27 04.10 +61 52 27.1           ~ 965 3
2 W 3(H2O) Mas 02 27 04.6 +61 52 25           ~ 124 0
3 IC 342 SBG 03 46 48.514 +68 05 45.98   10.5       ~ 1389 1
4 NAME Orion Core ? 05 35 14.5 -05 22 30           ~ 175 0
5 NAME Orion Bright Bar reg 05 35 22.30 -05 24 33.0           ~ 719 0
6 IRAS 16293-2422 cor 16 32 22.56 -24 28 31.8           ~ 1042 1
7 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11613 0
8 NAME Sgr B2M Mas 17 47 20.13 -28 23 06.1           ~ 35 1
9 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 1920 1
10 OH 34.26 +0.15 SFR 18 53 18.54 +01 14 57.9           ~ 462 0
11 LDN 1157 DNe 20 39 06.4 +68 02 13           ~ 485 0
12 [DE95] LDN 1157 B2 out 20 39 09.3 +68 00 44           ~ 59 0
13 [DE95] LDN 1157 B1 out 20 39 11 +68 01.3           ~ 181 0

    Equat.    Gal    SGal    Ecl

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2020.08.08-17:27:08

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