2015A&A...576A.129B


Query : 2015A&A...576A.129B

2015A&A...576A.129B - Astronomy and Astrophysics, volume 576A, 129-129 (2015/4-1)

Antifreeze in the hot core of Orion. First detection of ethylene glycol in Orion-KL.

BROUILLET N., DESPOIS D., LU X.-H., BAUDRY A., CERNICHARO J., BOCKELEE-MORVAN D., CROVISIER J. and BIVER N.

Abstract (from CDS):

Ices are present in comets and in the mantles of interstellar grains. Their chemical composition has been indirectly derived by observing molecules released in the gas phase, when comets approach the sun and when ice mantles are sublimated or destroyed, e.g. in the hot cores present in high-mass, star-forming regions. Comparison of these chemical compositions sheds light on the formation of comets and on the evolution of interstellar matter from the molecular cloud to a protoplanetary disk, and it shows, to first order, a good agreement between the cometary and interstellar abundances. However, a complex O-bearing organic molecule, ethylene glycol (CH2OH)2, seems to depart from this correlation because it was not easily detected in the interstellar medium (Sgr B2) although it proved to be rather abundant with respect to other O-bearing species in comet C/1995 O1 (Hale-Bopp). Ethylene glycol thus appears, together with the closely related molecules glycolaldehyde CH2OHCHO and ethanol CH3CH2OH, as a key species in the comparison of interstellar and cometary ices as well as in any discussion on the formation of cometary matter. It is important to measure the molecular abundances in various hot cores to see if the observed differences between the interstellar medium and the comets are general. We focus here on the analysis of ethylene glycol in the nearest and best studied hot core-like region, Orion-KL. We use ALMA interferometric data because high spatial resolution observations allow us to reduce the line confusion problem with respect to single-dish observations since different molecules are expected to exhibit different spatial distributions. Furthermore, a large spectral bandwidth is needed because many individual transitions are required to securely detect large organic molecules. Confusion and continuum subtraction are major issues and have been handled with care. We have detected the aGg' conformer of ethylene glycol in Orion-KL. The emission is compact and peaks towards the hot core close to the main continuum peak, about 2'' to the south-west; this distribution is notably different from other O-bearing species. Assuming optically thin lines and local thermodynamic equilibrium, we derive a rotational temperature of 145±30K and a column density of 4.6±0.8x1015cm–2. The limit on the column density of the gGg' conformer is five times lower.

Abstract Copyright:

Journal keyword(s): astrochemistry - ISM: molecules - radio lines: ISM - ISM: individual objects: Orion-KL - comets: general

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 - 2022
#notes
1 [JCC87] IRAS 2A Y*O 03 28 55.55 +31 14 36.7           ~ 435 3
2 V* V2254 Ori Or* 05 35 14.11296 -05 22 22.7316           B 305 2
3 NAME Orion-KL SFR 05 35 14.16 -05 22 21.5           ~ 2175 1
4 COUP 621 Y*O 05 35 14.35371 -05 22 32.8820           ~ 106 0
5 [FDB2011] MF2 mm 05 35 14.44 -05 22 34.4           ~ 6 0
6 [FDB2011] MF6 mm 05 35 14.50 -05 22 32.6           ~ 4 0
7 [RLK73] IRc 2 IR 05 35 14.51548 -05 22 30.5943           ~ 612 1
8 NAME Ori I As* 05 38 -02.8           ~ 587 0
9 NAME Galactic Center reg 17 45 39.60213 -29 00 22.0000           ~ 13179 0
10 NAME Sgr B2 MoC 17 47 20.4 -28 23 07           ~ 2122 1
11 NGC 7129 OpC 21 42 58 +66 06.8     11.5     ~ 248 0
12 NAME NGC 7129 FIR 2 IR 21 44 01.5 +66 03 40           ~ 93 0
13 NAME IRAS 16293-2422 East Red Lobe PoC ~ ~           ~ 9 0

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2022.09.24-18:29:45

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