2011A&A...527A..39B


C.D.S. - SIMBAD4 rel 1.7 - 2020.07.11CEST19:18:43

2011A&A...527A..39B - Astronomy and Astrophysics, volume 527A, 39-39 (2011/3-1)

Deuterated formaldehyde in ρ Ophiuchi A.

BERGMAN P., PARISE B., LISEAU R. and LARSSON B.

Abstract (from CDS):

Formaldehyde is an organic molecule that is abundant in the interstellar medium. High deuterium fractionation is a common feature in low-mass star-forming regions. Observing several isotopologues of molecules is an excellent tool for understanding the formation paths of the molecules. We seek an understanding of how the various deuterated isotopologues of formaldehyde are formed in the dense regions of low-mass star formation. More specifically, we adress the question of how the very high deuteration levels (several orders of magnitude above the cosmic D/H ratio) can occur using H2CO data of the nearby ρ Oph A molecular cloud. From mapping observations of H2CO, HDCO, and D2CO, we have determined how the degree of deuterium fractionation changes over the central 3'x3' region of ρ Oph A. The multi-transition data of the various H2CO isotopologues, as well as from other molecules (e.g., CH3OH and N2D+) present in the observed bands, were analysed using both the standard type rotation diagram analysis and, in selected cases, a more elaborate method of solving the radiative transfer for optically thick emission. In addition to molecular column densities, the analysis also estimates the kinetic temperature and H2 density. Toward the SM1 core in ρ Oph A, the H2CO deuterium fractionation is very high. In fact, the observed D2CO/HDCO ratio is 1.34±0.19, while the HDCO/H2CO ratio is 0.107±0.015. This is the first time, to our knowledge, that the D2CO/HDCO abundance ratio is observed to be greater than 1. The kinetic temperature is in the range 20-30K in the cores of ρ Oph A, and the H2 density is (6-10)x105cm–3. We estimate that the total H2 column density toward the deuterium peak is (1-4)x1023cm–2. As depleted gas-phase chemistry is not adequate, we suggest that grain chemistry, possibly due to abstraction and exchange reactions along the reaction chain H2CO -HDCO -D2CO, is at work to produce the very high deuterium levels observed.

Abstract Copyright:

Journal keyword(s): astrochemistry - ISM: abundances - ISM: clouds - ISM: individual objects: {rho} Ophiuchi A - ISM: molecules

Simbad objects: 19

goto Full paper

goto View the reference in ADS

Number of rows : 19

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 LDN 1527 DNe 04 39 53 +25 45.0           ~ 495 0
2 NAME Orion-KL SFR 05 35 14.16 -05 22 21.5           ~ 2001 1
3 NAME Orion Bright Bar reg 05 35 22.30 -05 24 33.0           ~ 716 0
4 WOS 48 C* 15 23 05.0744336371 -51 25 58.881494593   17.85 16.66 14.51 10.18 C 118 1
5 * rho Oph A * 16 25 35.1182364594 -23 26 49.827436721 4.3 5.22 5.05     B2/3V 389 0
6 GSS 30 Y*O 16 26 21.38160 -24 23 04.0524           ~ 200 1
7 [DAM2004] Oph A-N1 PoC 16 26 26.4 -24 23 07           ~ 4 0
8 NAME rho Oph A Cloud MoC 16 26 26.4 -24 22 33           ~ 238 1
9 NAME VLA 1623-243 Y*O 16 26 26.42 -24 24 30.0           ~ 373 0
10 NAME rho Oph A SM 1N cor 16 26 27.12 -24 23 34.8           ~ 43 0
11 [DAM2004] Oph A-N5 cor 16 26 27.4 -24 23 30           ~ 4 0
12 NAME rho Oph A SM 1 cor 16 26 27.60 -24 23 55.0           ~ 58 0
13 [JWM2000] SMM J16264-2422b PoC 16 26 28.3 -24 22 55           ~ 3 0
14 NAME rho Oph A SM 2 cor 16 26 30.4 -24 24 31           ~ 31 0
15 [DAM2004] Oph A-N6 cor 16 26 31.6 -24 24 52           ~ 15 0
16 NAME rho Oph C Cloud MoC 16 26 53.1 -24 32 31           ~ 54 0
17 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 3027 0
18 IRAS 16293-2422 cor 16 32 22.56 -24 28 31.8           ~ 1035 1
19 RAFGL 1922 C* 17 07 58.10976 -24 44 31.1820           C-rich 59 0

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2011A&A...527A..39B and select 'bookmark this link' or equivalent in the popup menu


2020.07.11-19:18:43

© Université de Strasbourg/CNRS

    • Contact