2005A&A...441..249V


C.D.S. - SIMBAD4 rel 1.7 - 2020.08.05CEST16:37:25

2005A&A...441..249V - Astronomy and Astrophysics, volume 441, 249 (2005/10-1)

A 3-5 µm VLT spectroscopic survey of embedded young low mass stars. II. Solid OCN.

VAN BROEKHUIZEN F.A., PONTOPPIDAN K.M., FRASER H.J. and VAN DISHOECK E.F.

Abstract (from CDS):

The 4.62µm (2164.5cm–1) ``XCN'' band has been detected in the M-band spectra of 34 deeply embedded young stellar objects (YSO's), observed with high signal-to-noise and high spectral resolution with the VLT-ISAAC spectrometer, providing the first opportunity to study the solid OCN abundance toward a large number of low-mass YSO's. It is shown unequivocally that at least two components, centred at 2165.7cm–1 (FWHM=26cm–1) and 2175.4cm–1 (FWHM=15cm–1), underlie the XCN band. Only the 2165.7-component can be ascribed to OCN, embedded in a strongly hydrogen-bonding, and possibly thermally annealed, ice environment based on laboratory OCN spectra. In order to correct for the contribution of the 2175.4-component to the XCN band, a phenomenological decomposition into the 2165.7- and the 2175.4-components is used to fit the full band profile and derive the OCN abundance for each line-of-sight. The same analysis is performed for 5 high-mass YSO's taken from the ISO-SWS data archive. Inferred OCN abundances are ≤0.85% toward low-mass YSO's and ≤1% toward high-mass YSO's, except for W33A. Abundances are found to vary by at least a factor of 10-20 and large source-to-source abundance variations are observed within the same star-forming cloud complex on scales down to 400AU, indicating that the OCN formation mechanism is sensitive to local conditions. The inferred abundances allow quantitatively for photochemical formation of OCN, but the large abundance variations are not easily explained in this scenario unless local radiation sources or special geometries are invoked. Surface chemistry should therefore be considered as an alternative formation mechanism.

Abstract Copyright:

Journal keyword(s): astrochemistry - line: identification - line: profiles - molecular data - ISM: abundances - ISM: lines and bands

Simbad objects: 49

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Number of rows : 49

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 IRAS 04016+2610 Y*O 04 04 43.07064 +26 18 56.3904           ~ 235 0
2 NAME Taurus Complex SFR 04 41.0 +25 52           ~ 3496 0
3 ISOY J053513.81-052340.1 Y*O 05 35 13.7814 -05 23 39.990           ~ 28 0
4 MLLA 293 Y*O 05 35 14.3976 -05 23 50.914           ~ 26 0
5 NAME Ori Region reg 05 35 17.30 -05 23 28.0           ~ 484 0
6 RAFGL 5163 Y*O 05 40 27.45024 -07 27 30.0564           ~ 125 1
7 NAME Mon R2 IRS 3 Y*O 06 07 47.8 -06 22 55           ~ 134 0
8 RAFGL 989 Y*O 06 41 10.1592954288 +09 29 33.635497596   17.4 16.8 18.26 17.28 B2 241 0
9 2MASS J08254384-5100326 Y*O 08 25 43.85 -51 00 32.7           ~ 298 1
10 NAME Vela XYZ Rad 08 34.0 -45 50           ~ 1114 2
11 IRAS 08448-4343 cor 08 46 33.8 -43 54 33           ~ 57 1
12 IRAS 08476-4306 cor 08 49 25.9 -43 17 10           ~ 27 0
13 [MHL2007] G264.9032+01.6584 1 Y*? 08 59 26.41 -43 26 13.4           ~ 10 0
14 IRAS 09014-4736 Y*? 09 03 09.4909851768 -47 48 27.777958701           ~ 23 1
15 HH 75 HH 09 11 38.5 -45 42 28           ~ 19 0
16 [PCW91] Ced 110 IRS 6A IR 11 07 09.91 -77 23 06.3           ~ 6 0
17 NAME Cha IR Nebula TT* 11 08 38.702 -77 43 51.54           M5.5 72 0
18 NAME Chamaeleon Region SFR 11 55 -78.0           ~ 690 0
19 NGC 4945 Sy2 13 05 27.279 -49 28 04.44   9.31 14.40 7.55   ~ 1267 2
20 VSSG 30 Y*O 16 26 44.19504 -24 34 48.3492           ~ 128 0
21 Elia 2-29 Y*O 16 27 09.43032 -24 37 18.7716           ~ 267 1
22 YLW 13B Y*O 16 27 21.46872 -24 41 43.0692           ~ 86 0
23 CRBR 2422.8-3423 Y*O 16 27 24.61320 -24 41 03.4080           ~ 81 1
24 YLW 15 Y*O 16 27 26.93640 -24 40 50.8224           ~ 241 1
25 YLW 16A Y*O 16 27 28.02744 -24 39 33.5052           K8 185 0
26 Elia 2-32 Y*O 16 27 28.44576 -24 27 21.0348           K6.5 104 1
27 YLW 16B Y*O 16 27 29.43528 -24 39 16.1892           ~ 102 0
28 Elia 2-33 Y*O 16 27 30.18024 -24 27 43.3656           M2 108 1
29 YLW 45 Y*O 16 27 39.82824 -24 43 15.0672           ~ 107 0
30 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3035 0
31 IRAS 16285-2355 Y*O 16 31 35.65752 -24 01 29.4708           ~ 103 0
32 HBC 650 TT* 16 34 29.32 -15 47 01.4           K3.0 165 2
33 GCIRS 19 * 17 45 41.087 -29 00 47.98           M4Ib 36 0
34 W 33a Y*O 18 14 39.0 -17 52 03           ~ 584 0
35 RAFGL 2136 SFR 18 22 26.8740 -13 30 17.177           ~ 245 0
36 NAME Serpens Cloud SFR 18 29 49 +01 14.8           ~ 917 2
37 HBC 672 Em* 18 29 56.8828626544 +01 14 46.339137067   17.6       K8.0 100 0
38 [EC89] SVS 4-5 Y*O 18 29 57.59 +01 13 00.6           ~ 30 1
39 IRAS 18274+0112 Y*O 18 29 57.73680 +01 14 05.6940           M4: 135 2
40 2MASS J18295785+0112514 Y*O 18 29 57.858 +01 12 51.40           ~ 58 3
41 CK 2 Y*O 18 30 00.618 +01 15 20.12           K5-M0III 52 0
42 RAFGL 7009S HII 18 34 20.911 -05 59 42.23           ~ 193 0
43 CHLT 3 * 19 01 48.10 -36 57 22.7           K6V 29 0
44 CHLT 4 * 19 01 48.15 -36 57 22.3           ~ 14 0
45 V* V710 CrA Or* 19 01 50.67792 -36 58 09.6132           K7: 117 0
46 NAME CrA Dark Cloud MoC 19 01 51 -36 58.9           ~ 397 0
47 2MASS J19015545-3657231 Y*O 19 01 55.460 -36 57 23.13           ~ 91 2
48 [NWA2005] SMM 1B Y*O 19 01 56.41 -36 57 28.0           ~ 80 1
49 [WBN74] NGC 7538 IRS 1 Y*O 23 13 45.318 +61 28 11.69           ~ 367 3

    Equat.    Gal    SGal    Ecl

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2020.08.05-16:37:25

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