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

Abstract

Comparison of their chemical compositions shows, to first order, a good agreement between the cometary and interstellar abundances. However, a complex O-bearing organic molecule, ethylene glycol (CH${}_2$OH)${}_2$, seems to depart from this correlation because it was not easily detected in the interstellar medium although it proved to be rather abundant with respect to other O-bearing species in comet Hale-Bopp. Ethylene glycol thus appears, together with the related molecules glycolaldehyde CH${}_2$OHCHO and ethanol CH${}_3$CH${}_2$OH, as a key species in the comparison of interstellar and cometary ices as well as in any discussion on the formation of cometary matter. 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 K and a column density of 4.6 10${}^{15}$ cm${}^{-2}$. The limit on the column density of the gGg' conformer is five times lower.

arXiv comment19 pages, 10 figures, A&A accepted

References in corpus (25)

• Complex organic molecules in the interstellar medium: IRAM 30 m line survey of Sagittarius B2(N) and (M)
• A Rigorous Attempt to Verify Interstellar Glycine
• Detection of the simplest sugar, glycolaldehyde, in a solar-type protostar with ALMA
• Complex organic molecules in protoplanetary disks
• The largest oxigen bearing organic molecule repository
• A line confusion limited millimeter survey of Orion KL (I): sulfur carbon chains
• Complex organic molecules in comets C/2012 F6 (Lemmon) and C/2013 R1 (Lovejoy): detection of ethylene glycol and formamide
• Explosive Disintegration of a Massive Young Stellar System in Orion
• First results from the CALYPSO IRAM-PdBI survey. II. Resolving the hot corino in the Class 0 protostar NGC 1333-IRAS2A
• A Multi-Epoch Study of the Radio Continuum Emission of Orion Source I: Constraints on the Disk Evolution of a Massive YSO and the Dynamical History of Orion BN/KL
• CH3OCH3 in Orion-KL: a striking similarity with HCOOCH3
• Unveiling Sources of Heating in the Vicinity of the Orion BN/KL Hot Core as Traced by Highly Excited Inversion Transitions of Ammonia
• High-Angular Resolution Dust Polarization Measurements: Shaped B-field Lines in the Massive Star Forming Region Orion BN/KL
• Deuterated methanol in Orion BN/KL
• The Orion Nebula in the mid-IR
• Submillimeter Array 440$\mu$m/690GHz line and continuum observations of Orion-KL
• The abundance of H2O and HDO in Orion KL from Herschel/HIFI
• A Spectral Line Survey of Selected 3 mm Bands Toward Sagittarius B2(N-LMH) Using the NRAO 12 Meter Radio Telescope and the BIMA Array I. The Observational Data
• Acetone in Orion BN/KL - High-resolution maps of a special oxygen-bearing molecule
• Complex Organic Molecules at High Spatial Resolution Toward Orion-KL II: Kinematics
• Complex Organic Molecules at High Spatial Resolution Toward Orion-KL I: Spatial Scales
• Discovery of an expanding molecular bubble in Orion BN/KL
• VLT/NACO infrared adaptive optics images of small scale structures in OMC1
• A High Spatial Resolution Study of the λ=3 mm Continuum of Orion-KL
• Physical Relation of Source I to IRc2 in the Orion KL Region

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• ALMA-IMF I -- Investigating the origin of stellar masses: Introduction to the Large Program and first results
• Complex organic molecules in comets from remote-sensing observations at millimeter wavelengths
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• The complexity of Orion: an ALMA view. II. gGg'-Ethylene Glycol and Acetic Acid
• Simulations of ice chemistry in cometary nuclei
• Widespread Presence of Glycolaldehyde and Ethylene Glycol Around Sagittarius B2
• Chemical modelling of glycolaldehyde and ethylene glycol in star-forming regions
• ALMA Observations of the Spatial Distribution of three C${}_2$H${}_4$O${}_2$ Isomers towards Sgr B2(N)
• ALMA-IMF XI: The sample of hot core candidates A rich population of young high-mass proto-stars unveiled by the emission of methyl formate
• Tentative detection of ethylene glycol toward W51/e2 and G34.3+0.2
• Is there any linkage between interstellar aldehyde and alcohol?
• ALMA Observations of Ethyl Formate toward Orion KL
• ALMA Detection of Vibrationally Excited ($v{}_{\mathrm{t}}=1,2$) Acetic Acid toward NGC 6334I
• Sulphur-Bearing and Complex Organic Molecules in an Infrared Cold Core
• Detection of antifreeze molecule ethylene glycol in the hot molecular core G358.93$-$0.03 MM1
• A deep Search for Ethylene Glycol and Glycolonitrile in the V883 Ori Protoplanetary Disk
• Unmasking the physical information inherent to interstellar spectral line profiles with Machine Learning. I. Application of LTE to HCN and HNC transitions