2011A&A...532A..32F


C.D.S. - SIMBAD4 rel 1.7 - 2019.11.17CET09:39:52

2011A&A...532A..32F - Astronomy and Astrophysics, volume 532A, 32-32 (2011/8-1)

HCOOCH3 as a probe of temperature and structure in Orion-KL.

FAVRE C., DESPOIS D., BROUILLET N., BAUDRY A., COMBES F., GUELIN M., WOOTTEN A. and WLODARCZAK G.

Abstract (from CDS):

The Orion Kleinmann-Low nebula (Orion-KL) is a complex region of star formation. Whereas its proximity allows studies on a scale of a few hundred AU, spectral confusion makes it difficult to identify molecules with low abundances. We studied an important oxygenated molecule, HCOOCH3, to characterize the physical conditions, temperature, and density of the different molecular source components. Methyl formate presents strong close rotational transitions covering a wide range of energy, and its emission in Orion-KL is not contaminated by the emission of N-bearing molecules. This study will help in the future 1) to constrain chemical models for the formation of methyl formate in gas phase or on grain mantles and 2) to search for more complex or prebiotic molecules. We used high-resolution observations from the IRAM Plateau de Bure Interferometer to reduce spectral confusion and to better isolate the molecular emission regions. We used twelve data sets with a spatial resolution down to 1.8''x0.8''. Continuum emission was subtracted by selecting apparently line-free channels. We identify 28 methyl formate emission peaks throughout the 50'' field of observations. The two strongest peaks, named MF1 and MF2, are in the Compact Ridge and in the southwest of the Hot Core, respectively. From a comparison with single-dish observations, we estimate that we miss less than 15% of the flux and that spectral confusion is still prevailing as half of the expected transitions are blended over the region. Assuming that the transitions are thermalized, we derive the temperature at the five main emission peaks. At the MF1 position in the Compact Ridge we find a temperature of 80K in a 1.8''x0.8'' beam size and 120K on a larger scale (3.6''x2.2''), suggesting an external source of heating, whereas the temperature is about 130K at the MF2 position on both scales. Transitions of methyl formate in its first torsionally excited state are detected as well, and the good agreement of the positions on the rotational diagrams between the ground state and the vt=1 transitions suggests a similar temperature. The LSR velocity of the gas is between 7.5 and 8.0km/s depending on the positions and column density peaks vary from 1.6x1016 to 1.6x1017cm–2. A second velocity component is observed around 9-10km/s in a north-south structure stretching from the Compact Ridge up to the BN object, and this component is warmer at the MF1 peak. The two other C2H4O2 isomers are not detected, and the derived upper limit for the column density is ≤3x1014m–2 for glycolaldehyde and ≤2x1015cm–2 for acetic acid. From the 223GHz continuum map, we identify several dust clumps with associated gas masses in the range 0.8 to 5.8M. Assuming that the methyl formate is spatially distributed as the dust is, we find relative abundances of methyl formate in the range ≤0.1x10–8 to 5.2x10–8. We suggest a relation between the methyl formate distribution and shocks as traced by 2.12µm H2 emission.

Abstract Copyright:

Journal keyword(s): astrochemistry - ISM: molecules - radio lines: ISM - ISM: individual objects: Orion-KL

VizieR on-line data: <Available at CDS (J/A+A/532/A32): HCOOCH3.fit>

Nomenclature: Fig. 4, Table 2: [FDB2011] MFNN (Nos MF1-MF28). Fig. 16, Tables 7-8: [FDB2011] CaN (Nos Ca-Cd, Cb1-Cb2).

Simbad objects: 86

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Number of rows : 86

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 W 3 IRS 5 Cluster Cl* 02 25 42 +62 06.1           ~ 71 1
2 QSO B0420-0127 QSO 04 23 15.80072776 -01 20 33.0654034   17.50 17.00 16.28   ~ 1020 2
3 4C -02.19 QSO 05 01 12.80988366 -01 59 14.2562534   19.1 18.4 19.04   ~ 505 1
4 QSO J0530+13 QSO 05 30 56.41672 +13 31 55.1495     20.0 19.35   ~ 871 1
5 NAME Super Water Maser in Orion Mas 05 35.2 -05 22           ~ 12 0
6 [FDB2011] MF20 mm 05 35 13.46 -05 22 36.6           ~ 1 0
7 [FDB2011] MF18 mm 05 35 13.46 -05 22 30.8           ~ 1 0
8 [FDB2011] MF22 mm 05 35 13.61 -05 22 41.3           ~ 1 0
9 [FDB2011] MF21 mm 05 35 13.64 -05 22 39.3           ~ 1 0
10 [FDB2011] MF19 mm 05 35 13.66 -05 22 31.5           ~ 1 0
11 [FDB2011] MF15 mm 05 35 13.72 -05 22 14.0           ~ 1 0
12 [FDB2011] MF16 mm 05 35 13.73 -05 22 19.1           ~ 1 0
13 [FDB2011] MF27 mm 05 35 13.92 -05 22 50.3           ~ 1 0
14 [FW2011] J053513.988-052244.887 mm 05 35 13.988 -05 22 44.89           ~ 5 0
15 [FDB2011] MF28 mm 05 35 14.00 -05 22 35.3           ~ 3 0
16 NAME OMC-1 MoC 05 35 14 -05 22.4           ~ 991 2
17 [FDB2011] Cb2 mm 05 35 14.010 -05 22 37.24           ~ 2 0
18 [RLK73] IRc 3N IR 05 35 14.01 -05 22 30.1           ~ 5 0
19 [RLK73] IRc 3S IR 05 35 14.02 -05 22 30.8           ~ 5 0
20 [FDB2011] Cd mm 05 35 14.030 -05 22 44.60           ~ 1 0
21 [FDB2011] MF7 mm 05 35 14.05 -05 22 42.3           ~ 1 0
22 Parenago 1822 *iN 05 35 14.07 -05 22 36.6     15.906   12.799 M3 46 0
23 [FDB2011] Cb1 mm 05 35 14.080 -05 22 36.73           ~ 3 0
24 [FDB2011] Cc mm 05 35 14.080 -05 22 27.50           ~ 2 0
25 [FDB2011] MF1 mm 05 35 14.09 -05 22 36.7           ~ 4 0
26 [FDB2011] MF13 mm 05 35 14.09 -05 22 32.5           ~ 2 0
27 [FW2011] J053514.096-052226.734 IR 05 35 14.096 -05 22 26.73           ~ 6 0
28 [FDB2011] MF9 mm 05 35 14.11 -05 22 43.3           ~ 1 0
29 V* V2254 Ori Or* 05 35 14.113 -05 22 22.73           B 277 2
30 [FDB2011] MF5 mm 05 35 14.12 -05 22 27.7           ~ 5 0
31 [GD77] B IR 05 35 14.15 -05 22 37.4           ~ 30 0
32 [FDB2011] MF4 mm 05 35 14.15 -05 22 29.3           ~ 3 0
33 [FDB2011] MF14 mm 05 35 14.16 -05 22 37.0           ~ 3 0
34 [RLK73] IRc 20 IR 05 35 14.16 -05 22 29.8           ~ 12 0
35 NAME Orion-KL SFR 05 35 14.16 -05 22 21.5           ~ 1945 1
36 [RLK73] IRc 6 IR 05 35 14.18 -05 22 26.7           ~ 36 0
37 [FDB2011] MF12 mm 05 35 14.18 -05 22 34.6           ~ 4 0
38 [GD77] A IR 05 35 14.19 -05 22 34.0           ~ 58 0
39 [FDB2011] MF8 mm 05 35 14.20 -05 22 46.1           ~ 1 0
40 [FW2011] J053514.253-052227.820 IR 05 35 14.253 -05 22 27.82           ~ 6 0
41 [FW2011] J053514.278-052230.647 IR 05 35 14.278 -05 22 30.65           ~ 68 0
42 [RLK73] IRc 17 IR 05 35 14.28 -05 22 20.1           ~ 7 0
43 [FDB2011] MF3 mm 05 35 14.31 -05 22 37.2           ~ 2 0
44 [CBA97] 8 * 05 35 14.33 -05 22 25.2           ~ 13 0
45 NAME Ori N Y*O 05 35 14.35371 -05 22 32.8820           ~ 100 0
46 [FDB2011] MF26 mm 05 35 14.38 -05 22 49.4           ~ 1 0
47 [RLK73] IRc 16W IR 05 35 14.39 -05 22 22.7           ~ 5 0
48 [RLK73] IRc 2c X 05 35 14.39867 -05 22 30.3648           ~ 22 0
49 [RLK73] IRc 21 IR 05 35 14.41 -05 22 27.9           ~ 6 0
50 [FDB2011] MF2 mm 05 35 14.44 -05 22 34.4           ~ 6 0
51 [RLK73] IRc 2e IR 05 35 14.44 -05 22 29.2           ~ 3 0
52 [FDB2011] MF17 mm 05 35 14.44 -05 22 24.0           ~ 1 0
53 [FDB2011] MF11 mm 05 35 14.45 -05 22 30.6           ~ 2 0
54 [RLK73] IRc 2d IR 05 35 14.45 -05 22 29.9           ~ 19 0
55 [RLK73] IRc 16N IR 05 35 14.45 -05 22 21.6           ~ 4 0
56 [RLK73] IRc 2b IR 05 35 14.473 -05 22 29.61           ~ 20 0
57 JCMTSE J053514.4-052232 Y*? 05 35 14.488 -05 22 32.10           ~ 46 0
58 [RLK73] IRc 16S IR 05 35 14.49 -05 22 23.7           ~ 5 0
59 [FDB2011] MF6 mm 05 35 14.50 -05 22 32.6           ~ 4 0
60 LBLS q IR 05 35 14.50 -05 22 16.0           ~ 7 0
61 [RLK73] IRc 2a Y*O 05 35 14.511 -05 22 30.40           ~ 112 0
62 [RLK73] IRc 2 IR 05 35 14.51548 -05 22 30.5943           ~ 560 1
63 [RLK73] IRc 22 IR 05 35 14.55 -05 22 34.2           ~ 4 0
64 [FDB2011] Ca mm 05 35 14.560 -05 22 31.50           ~ 1 0
65 [RLK73] IRc 23 IR 05 35 14.57 -05 22 21.1           ~ 5 0
66 Parenago 1839 *iN 05 35 14.64 -05 22 33.7   15.891 14.779   12.008 K7 49 0
67 [FDB2011] MF24 mm 05 35 14.68 -05 22 36.7           ~ 1 0
68 [RLK73] IRc 8 IR 05 35 14.68 -05 22 35.1           ~ 8 0
69 [FDB2011] MF10 mm 05 35 14.68 -05 22 28.9           ~ 3 0
70 [RLK73] IRc 11 IR 05 35 14.71 -05 22 30.8           ~ 8 0
71 [RLK73] IRc 12 IR 05 35 14.81 -05 22 31.3           ~ 10 0
72 [FDB2011] MF23 mm 05 35 15.01 -05 22 34.8           ~ 1 0
73 MLLA 646 IR 05 35 15.08 -05 22 30.1           ~ 8 0
74 [RLK73] IRc 13 IR 05 35 15.09 -05 22 27.7           ~ 6 0
75 [FDB2011] MF25 mm 05 35 15.20 -05 22 38.7           ~ 1 0
76 NAME Trapezium Cluster As* 05 35 16.5 -05 23 14           ~ 1433 1
77 M 42 HII 05 35 17.3 -05 23 28           ~ 3658 0
78 Haro 4-355 Em* 05 35 21.3313111928 -05 53 51.793164995     13.7 14.38   M0.7 8 0
79 V* V357 Ori Or* 05 35 21.5792456705 -05 09 49.679398391     17.06   14.590 M3 39 0
80 NAME Ori I As* 05 38 -02.8           ~ 545 0
81 NAME ORI MOL CLOUD MoC 05 56 -01.8           ~ 812 1
82 QSO B0605-0834 QSO 06 07 59.69923743 -08 34 49.9781718     18.5 17.70   ~ 381 1
83 QSO B0607-157 QSO 06 09 40.9477650070 -15 42 40.649794982   18.47 18.0 19.90   ~ 282 1
84 NAME Sgr B2 (North) Rad 17 47 20.2 -28 22 21           ~ 497 1
85 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 1857 1
86 LDN 1157 DNe 20 39 06.4 +68 02 13           ~ 463 0

    Equat.    Gal    SGal    Ecl

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2019.11.17-09:39:52

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