2006A&A...453..949P


C.D.S. - SIMBAD4 rel 1.7 - 2019.10.18CEST14:29:32

2006A&A...453..949P - Astronomy and Astrophysics, volume 453, 949-958 (2006/7-3)

Testing grain surface chemistry: a survey of deuterated formaldehyde and methanol in low-mass class 0 protostars.

PARISE B., CECCARELLI C., TIELENS A.G.G.M., CASTETS A., CAUX E., LEFLOCH B. and MARET S.

Abstract (from CDS):

Despite the low cosmic abundance of deuterium (D/H∼10–5), high degrees of deuterium fractionation in molecules are observed in star-forming regions with enhancements that can reach 13 orders of magnitude, a level that current models have difficulty accounting for. Multi-isotopologue observations are a very powerful constraint for chemical models. The aim of our observations is to understand the processes that form the observed high abundances of methanol and formaldehyde in low-mass protostellar envelopes (gas-phase processes? chemistry on the grain surfaces?), as well as to better constrain the chemical models. With the IRAM 30m single-dish telescope, we observed deuterated formaldehyde (HDCO and D2CO) and methanol (CH2DOH, CH3OD, and CHD2OH) towards a sample of seven low-mass class 0 protostars. Using population diagrams, we then derived the fractionation ratios of these species (abundance ratio between the deuterated molecule and its main isotopologue) and compared them to the predictions of grain chemistry models. These protostars show a similar level of deuteration as in IRAS 16293-2422, where doubly-deuterated methanol - and even triply-deuterated methanol - were first detected. Our observations point to the formation of methanol on the grain surfaces, while formaldehyde formation cannot be fully pinned down. While none of the scenarii can be excluded (gas-phase or grain chemistry formation), they both seem to require abstraction reactions to reproduce the observed fractionations.

Abstract Copyright:

Journal keyword(s): ISM: abundances - ISM: molecules - stars: formation

Simbad objects: 17

goto Full paper

goto View the reference in ADS

Number of rows : 17

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 IRAS 03225+3034 IR 03 25 36.49 +30 45 22.2           ~ 149 1
2 SSTc2d J032536.4+304522 Y*O 03 25 36.49 +30 45 22.2           ~ 184 1
3 LDN 1448NA smm 03 25 36.49 +30 45 22.2           ~ 170 1
4 [SDA2014] West4 Y*O 03 25 38.83 +30 44 06.2           ~ 241 1
5 NAME LDN 1448-mm Y*O 03 25 38.83 +30 44 06.2           ~ 293 0
6 IRAS 03258+3104 Y*O 03 28 55.30 +31 14 27.8           ~ 158 1
7 [JCC87] IRAS 2A Y*O 03 28 55.55 +31 14 36.7           ~ 371 3
8 [JCC87] IRAS 4A Y*O 03 29 10.49 +31 13 30.8           ~ 566 1
9 [JCC87] IRAS 4 FIR 03 29 10.9 +31 13 26           ~ 462 0
10 [JCC87] IRAS 4B Y*O 03 29 12.058 +31 13 02.05           ~ 544 0
11 NAME Per Region reg 03 37 00.0 +31 15 00           ~ 221 0
12 LDN 1527 DNe 04 39 53 +25 45.0           ~ 468 0
13 NAME Taurus Dark Cloud SFR 04 41.0 +25 52           ~ 3308 0
14 NAME Ophiuchus Molecular Cloud SFR 16 28 06 -24 32.5           ~ 2929 0
15 IRAS 16293-2422 cor 16 32 22.56 -24 28 31.8           ~ 998 1
16 NAME LDN 1157-mm Y*O 20 39 06.2 +68 02 15           ~ 152 0
17 NAME NGC 7129 FIR 2 IR 21 44 01.5 +66 03 40           ~ 80 0

    Equat.    Gal    SGal    Ecl

To bookmark this query, right click on this link: simbad:objects in 2006A&A...453..949P and select 'bookmark this link' or equivalent in the popup menu


2019.10.18-14:29:32

© Université de Strasbourg/CNRS

    • Contact