2021A&A...656A.148R

Query : 2021A&A...656A.148R

2021A&A...656A.148R - Astronomy and Astrophysics, volume 656A148-148 (2021/12-1)

Mechanisms for gas-phase molecular formation of neutral formaldehyde (H2CO) in cold astrophysical regions.

RAMAL-OLMEDO J.C., MENOR-SALVAN C.A. and FORTENBERRY R.C.

Abstract (from CDS):


Context. Formaldehyde is a potential biogenic precursor involved in prebiotic chemical evolution. The cold conditions of the interstellar medium (ISM) allow H2CO to be reactive, playing a significant role as a chemical intermediate in formation pathways leading to interstellar complex organic molecules. However, gas-phase molecular formation mechanisms in cold regions of the ISM are poorly understood.
Aims. We computationally determine the most favored gas-phase molecular formation mechanisms at local thermodynamic equilibrium conditions that can produce the detected amounts of H2CO in diffuse molecular clouds (DMCs), in dark, cold, and dense molecular clouds (DCDMCs), and in three regions of circumstellar envelopes of low-mass protostars (CELMPs).
Methods. The potential energy surfaces, thermodynamic functions, and single-point energies for transition states were calculated at the CCSD(T)-F12/cc-pVTZ-F12 and MP2/aug-cc-pVDZ levels of theory and basis sets. Molecular thermodynamics and related partition functions were obtained by applying the Maxwell-Boltzmann quantum statistics theory from energies computed at CCSD(T)-F12/cc-pVTZ-F12 with corrections for zero-point energy. A literature review on detected abundances of reactants helped us to propose the most favorable formation routes.
Results. The most probable reactions that produce H2CO in cold astrophysical regions are: 1CH2 + .3O2 ⟶ 1H2CO + O.(3P) in DMCs, .3CH2 + .3O2 ⟶ 1H2CO + .O(3P) in DCDMCs, and .CH3 + .O(3P) ⟶ 1H2CO + .H in region III, .CH3 + .O(1D) ⟶ 1H2CO + .H in region II, and 1CH2 + .3O2 ⟶ 1H2CO + .O(3P) in region I belonging to CELMPs.
Conclusions. Quantum chemical calculations suggest that the principal carbonaceous precursors of H2CO in cold regions for the gas-phase are CH2(a1A1), and .CH2(X3B1) combined with .O2(3Σg) and .CH3(2A") + .O(3P)/ O(1D). Reactions based on more complex reagents yield less effective thermodynamics in the gas-phase H2CO molecular formation.

Abstract Copyright: © ESO 2021

Journal keyword(s): astrobiology - astrochemistry - ISM: molecules - molecular processes

Simbad objects: 72

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Number of rows : 72
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2026 		#notes
1 W 3 MoC 02 27 04.10 +61 52 27.1           ~ 1064 3
2 SSTc2d J032536.4+304522 Y*O 03 25 36.49 +30 45 22.2           ~ 208 1
3 IRAS F03226+3033 Y*O 03 25 38.83 +30 44 06.2           ~ 371 0
4 IRAS 03258+3104 Y*O 03 28 55.30 +31 14 27.8           ~ 173 1
5 NGC 1333 OpC 03 29 09.2 +31 20 59           ~ 1575 1
6 [JCC87] IRAS 4A Y*O 03 29 10.49 +31 13 30.8           ~ 770 1
7 [JCC87] IRAS 4B Y*O 03 29 12.058 +31 13 02.05           ~ 625 0
8 V* IK Tau OH* 03 53 28.8924743304 +11 24 21.895183368 16.99 14.463 16.171 14.101   M7-11 675 0
9 6C 035545+504923 Bla 03 59 29.74727351 +50 57 50.1618607           ~ 480 1
10 LDN 1495 DNe 04 18.1 +27 37           ~ 408 1
11 4C 27.13 Rad 04 19 11.13090 +27 12 08.2110           ~ 11 1
12 Barnard 219 DNe 04 34 +29.6           ~ 3 0
13 NAME Per B SyG 04 37 04.37535450 +29 40 13.8179631   21.7       ~ 533 2
14 LDN 1527 DNe 04 39 53 +25 45.0           ~ 689 0
15 TMC-1 MoC 04 41 45.9 +25 41 27           ~ 1872 0
16 RAFGL 618 pA* 04 42 53.6242032600 +36 06 53.400902220   16.32   12.59   C-rich 1027 0
17 NAME Orion-KL SFR 05 35 14.16 -05 22 21.5           ~ 2421 1
18 NAME Ori Region reg 05 35 17.30 -05 23 28.0           ~ 623 0
19 LDN 1641 MoC 05 39.0 -07 00           ~ 502 0
20 NGC 2024 Cl* 05 41 43 -01 50.5           ~ 1198 1
21 LDN 1630 DNe 05 45.5 -00 59           ~ 392 0
22 LDN 1570 DNe 06 07 28.4 +19 28 04           ~ 46 0
23 NAME Mon R2 HII 06 07 47.58 -06 22 42.6           ~ 789 2
24 LDN 1605 DNe 06 32.8 +10 38           ~ 16 0
25 NGC 2264 OpC 06 40 53.7 +09 52 32           ~ 1876 0
26 OH 231.8+04.2 OH* 07 42 16.947 -14 42 50.20           M10III+A 548 0
27 IRC +10216 C* 09 47 57.40632 +13 16 43.5648           C9,5e 2455 0
28 M 82 AGN 09 55 52.430 +69 40 46.93 9.61 9.30 8.41     ~ 6156 6
29 V* TW Hya TT* 11 01 51.9053285064 -34 42 17.033218380   11.94 10.50 10.626 9.18 K6Ve 2144 1
30 LDN 134 MoC 15 53 36.3 -04 35 26           ~ 217 0
31 LDN 183 MoC 15 54 12.2 -02 49 42           ~ 799 1
32 NAME VLA 1623-243 Y*O 16 26 26.42 -24 24 30.0           ~ 429 0
33 HCL 4 Cld 16 27.2 -24 11           ~ 4 0
34 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3969 1
35 IRAS 16293-2422 cor 16 32 22.56 -24 28 31.8           ~ 1357 1
36 LDN 1689N DNe 16 32 25.96 -24 28 46.2           ~ 121 0
37 NAME Draco Nebula RNe 16 52 +61.0           ~ 58 0
38 LDN 1759 DNe 16 52.1 -23 05           ~ 8 0
39 NGC 6334 HII 17 20 53 -36 07.9           ~ 740 0
40 LDN 57 DNe 17 22 38.2 -23 49 34           ~ 336 1
41 NAME Snake DCld DNe 17 23 39 -23 41.7           ~ 22 0
42 NAME Sgr A* X 17 45 40.03599 -29 00 28.1699           ~ 4970 3
43 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 2443 1
44 HD 163296 Ae* 17 56 21.2881851168 -21 57 21.871819008 7.00 6.93 6.85 6.86 6.67 A3VaekA1mA1 1301 0
45 W 33 SFR 18 14 14.0 -17 55 50           ~ 292 0
46 W 33a Y*O 18 14 39.56547 -17 52 02.2260           ~ 746 0
47 M 18 OpC 18 19 56.2 -17 04 21           ~ 93 0
48 NGC 6618 OpC 18 20 47 -16 10.3           ~ 1700 0
49 RAFGL 7009S HII 18 34 20.911 -05 59 42.23           ~ 231 0
50 GPSR 024.799+0.097 Rad 18 36 14.4 -07 10 47           ~ 5 0
51 LDN 485 DNe 18 36.7 -06 57           ~ 6 0
52 W 43 SFR 18 47 32 -01 56.5           ~ 604 0
53 SNR G034.6-00.5 SNR 18 56 10.650 +01 13 21.30           ~ 1034 2
54 LDN 628 DNe 18 58.5 +03 26           ~ 6 0
55 LDN 531 DNe 19 06 10.0 -06 53 45           ~ 67 0
56 LDN 543 DNe 19 06.7 -06 10           ~ 25 0
57 W 49 SFR 19 10 20 +09 07.7           ~ 601 1
58 W 51 SNR 19 23 50 +14 06.0           ~ 1352 1
59 LDN 663 DNe 19 36 55 +07 34.4           ~ 698 0
60 RAFGL 2591 Y*O 20 29 24.8230 +40 11 19.590           ~ 640 0
61 DR 17 HII 20 35.2 +42 25           ~ 50 0
62 LDN 906 DNe 20 36.8 +42 11           ~ 9 0
63 DR 21 SFR 20 39 01.6 +42 19 38           O4.5 1121 0
64 NAME LDN 1157-mm Y*O 20 39 06.2 +68 02 15           ~ 204 0
65 NGC 7293 PN 22 29 38.5454047152 -20 50 13.747242408 11.894 13.158 13.524 13.689 13.898 DAO.5 983 1
66 HCL 1 Cld 22 37.0 +75 14           ~ 4 0
67 IC 1470 HII 23 05 09.9 +60 14 31   11.5       ~ 180 2
68 NGC 7538 OpC 23 13 37 +61 30.0           ~ 920 1
69 NGC 7538S Y*O 23 13 44.8 +61 26 51           ~ 91 1
70 [WBN74] NGC 7538 IRS 1 Y*O 23 13 45.318 +61 28 11.69           ~ 433 3
71 IRAS 23118+6110 Y*O 23 14 02.09473 +61 27 18.8460           ~ 385 0
72 NAME Cas A SNR 23 23 26.0 +58 48 41     14.30     ~ 3033 1

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