2017A&A...607A..20T


Query : 2017A&A...607A..20T

2017A&A...607A..20T - Astronomy and Astrophysics, volume 607A, 20-20 (2017/11-1)

Chemical complexity induced by efficient ice evaporation in the Barnard 5 molecular cloud.

TAQUET V., WIRSTROM E.S., CHARNLEY S.B., FAURE A., LOPEZ-SEPULCRE A. and PERSSON C.M.

Abstract (from CDS):

Cold gas-phase water has recently been detected in a cold dark cloud, Barnard 5 located in the Perseus complex, by targeting methanol peaks as signposts for ice mantle evaporation. Observed morphology and abundances of methanol and water are consistent with a transient non-thermal evaporation process only affecting the outermost ice mantle layers, possibly triggering a more complex chemistry. Here we present the detection of the complex organic molecules (COMs) acetaldehyde (CH3CHO) and methyl formate (CH3OCHO), as well as formic acid (HCOOH) and ketene (CH2CO), and the tentative detection of di-methyl ether (CH3OCH3) towards the "methanol hotspot" of Barnard 5 located between two dense cores using the single dish OSO 20 m, IRAM 30 m, and NRO 45m telescopes. The high energy cis-conformer of formic acid is detected, suggesting that formic acid is mostly formed at the surface of interstellar grains and then evaporated. The detection of multiple transitions for each species allows us to constrain their abundances through LTE and non-LTE methods. All the considered COMs show similar abundances between ∼1 and ∼10% relative to methanol depending on the assumed excitation temperature. The non-detection of glycolaldehyde, an isomer of methyl formate, with a [glycolaldehyde]/[methyl formate] abundance ratio lower than 6%, favours gas phase formation pathways triggered by methanol evaporation. According to their excitation temperatures derived in massive hot cores, formic acid, ketene, and acetaldehyde have been designated as "lukewarm" COMs whereas methyl formate and di-methyl ether were defined as "warm" species. Comparison with previous observations of other types of sources confirms that lukewarm and warm COMs show similar abundances in low-density cold gas whereas the warm COMs tend to be more abundant than the lukewarm species in warm protostellar cores. This abundance evolution suggests either that warm COMs are indeed mostly formed in protostellar environments and/or that lukewarm COMs are efficiently depleted by increased hydrogenation efficiency around protostars.

Abstract Copyright: © ESO, 2017

Journal keyword(s): astrochemistry - ISM: abundances - ISM: clouds - ISM: molecules - molecular processes - stars: formation - stars: formation

Simbad objects: 13

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Number of rows : 13
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 [JCC87] IRAS 2A Y*O 03 28 55.55 +31 14 36.7           ~ 421 3
2 [HKM99] B1-b cor 03 33 20.32 +31 07 21.5           ~ 178 0
3 NAME Perseus Cloud SFR 03 35.0 +31 13           ~ 1155 0
4 IRAS 03445+3242 Y*O 03 47 41.603 +32 51 43.79           ~ 180 0
5 LDN 1471 DNe 03 48.0 +32 54           ~ 299 0
6 TMC-1 MoC 04 41 45.9 +25 41 27           ~ 1450 0
7 LDN 1544 DNe 05 04 16.6 +25 10 48           ~ 740 0
8 NAME Orion Bright Bar reg 05 35 22.30 -05 24 33.0           ~ 773 0
9 NAME Horsehead Nebula DNe 05 40 59.0 -02 27 30           ~ 463 0
10 LDN 183 MoC 15 54 12.2 -02 49 42           ~ 710 1
11 IRAS 16293-2422 cor 16 32 22.56 -24 28 31.8           ~ 1113 1
12 LDN 1689B DNe 16 34 42.1 -24 36 11           ~ 149 0
13 [MBS2007c] CygX-N44 Rad 20 39 01.01 +42 22 50.2           ~ 370 0

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2021.09.27-18:47:38

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