CH3OCH3 in Orion-KL: a striking similarity with HCOOCH3

Abstract

We used several data sets from the Plateau de Bure Interferometer to map the dimethyl ether emission in Orion-KL with different arcsec spatial resolutions and different energy levels to compare with our previous methyl formate maps. Our data show remarkable similarity between the dimethyl ether (CH3OCH3) and the methyl formate (HCOOCH3) distributions even on a small scale (1.8"x0.8" or about 500 AU). This long suspected similarity, seen from both observational and theoretical arguments, is demonstrated with unprecedented confidence, with a correlation coefficient of maps of 0.8. A common precursor is the simplest explanation of our correlation. Comparisons with previous laboratory work and chemical models suggest the major role of grain surface chemistry and a recent release, probably with little processing, of mantle molecules by shocks. In this case the CH3O radical produced from methanol ice would be the common precursor (whereas ethanol, C2H5OH, is produced from the radical CH2OH). The alternative gas phase scheme, where protonated methanol CH3OH2+ is the common precursor to produce methyl formate and dimethyl ether through reactions with HCOOH and CH3OH, is also compatible with our data. Our observations cannot yet definitely allow a choice between the different chemical processes, but the tight correlation between the distributions of HCOOCH3 and CH3OCH3 strongly contrasts with the different behavior we observe for the distributions of ethanol and formic acid. This provides a very significant constraint on models.

10 pages, 8 figures, to be published in Astronomy & Astrophysics

References in corpus (9)

• Complex Chemistry in Star-Forming Regions: An Expanded Gas-Grain Warm-up Chemical Model
• The distance to the Orion Nebula
• Testing grain-surface chemistry in massive hot-core regions
• The largest oxigen bearing organic molecule repository
• A Parallactic Distance of 389 +24/-21 parsecs to the Orion Nebula Cluster from Very Long Baseline Array Observations
• Organic Molecules in the Galactic Center. Hot Core Chemistry without Hot Cores
• Proplyds and Massive Disks in the Orion Nebula Cluster Imaged with CARMA and SMA
• High Resolution $\lambda$=1mm CARMA Observations of Large Molecules in Orion-KL
• A 3D view of the outflow in the Orion Molecular Cloud 1 (OMC-1)

Cited by in corpus (41)

• Astrochemistry During the Formation of Stars
• Formation of Complex Organic Molecules in Cold Interstellar Environments through non-diffusive grain-surface and ice-mantle chemistry
• Questioning the spatial origin of complex organic molecules in young protostars with the CALYPSO survey
• Herschel observations of EXtra-Ordinary Sources: Analysis of the HIFI 1.2 THz Wide Spectral Survey Toward Orion KL I. Methods
• Discovery of Methyl Acetate and Gauche Ethyl Formate in Orion
• The census of complex organic molecules in the solar type protostar IRAS16293-2422
• Evolutionary study of complex organic molecules in high-mass star-forming regions
• Antifreeze in the hot core of Orion - First detection of ethylene glycol in Orion-KL
• Searching for Trans Ethyl Methyl Ether in Orion KL
• Complex organic molecules in comets from remote-sensing observations at millimeter wavelengths
• The abundance of H2O and HDO in Orion KL from Herschel/HIFI
• Chemical segregation of complex organic O-bearing species in Orion KL
• First Hot Corino detected around an Isolated Intermediate-Mass Protostar: Cep\,E-mm
• Acetone in Orion BN/KL - High-resolution maps of a special oxygen-bearing molecule
• The hot core towards the intermediate mass protostar NGC7129 FIRS 2: Chemical similarities with Orion KL
• Interstellar Glycolaldehyde, Methyl Formate, and Acetic Acid I: A Bi-modal Abundance Pattern in Star Forming Regions
• The Difference in Abundances between N-bearing and O-bearing Species in High-Mass Star-Forming Regions
• Organic chemistry in the protosolar analogue HOPS-108: Environment matters
• Processing of formic acid-containing ice by heavy and energetic cosmic ray analogues
• Mapping Observations of complex organic molecules around Sagittarius B2 with ARO 12m telescope
• VERA and ALMA Observations of the H2O Supermaser Burst in Orion KL
• ALMA Observations of the Spatial Distribution of three C${}_2$H${}_4$O${}_2$ Isomers towards Sgr B2(N)
• Evolution of complex organic molecules in hot molecular cores: Synthetic spectra at (sub-)mm wavebands
• Sulphur-rich cold gas around the hot core precursor G328.2551-0.5321. An APEX unbiased spectral survey of the 2 mm, 1.2 mm, and 0.8 mm atmospheric windows
• Complex organic molecules detected in twelve high-mass star-forming regions with Atacama Large Millimeter/submillimeter Array (ALMA)
• ALMA Observations of Ethyl Formate toward Orion KL
• Complex molecules in W51 North region
• Complex organic molecules uncover deeply embedded precursors of hot cores
• SPARKS II.: Complex organic molecules in accretion shocks around a hot core precursor
• Observational evidence for rotational desorption of Complex Molecules by radiative torques from Orion BN/KL
• A spectroscopic survey of Orion KL between 41.5 and 50 GHz
• ALMA imaging study of methyl formate (HCOOCH${}_3$) in the torsionally excited states towards Orion KL
• New spectral characterization of dimethyl ether isotopologues CH${}_3$OCH${}_3$ and ${}^{13}$CH${}_3$OCH${}_3$ in the THz region
• The GBT 67 -- 93.6 GHz Spectral Line Survey of Orion-KL
• Sulphur-Bearing and Complex Organic Molecules in an Infrared Cold Core
• Infrared action spectroscopy as tool for probing gas-phase dynamics: Protonated Dimethyl Ether, (CH${}_3$)${}_2$OH${}^{+}$, formed by the reaction of CH${}_3$OH${}_2^{+}$ with CH${}_3$OH
• The distribution of deuterated formaldehyde within Orion-KL
• CARMA $\lambda$ = 1 cm Spectral Line Survey of Orion-KL
• Molecular complexity on disk-scales uncovered by ALMA: The chemical composition of the high-mass protostar AFGL 4176
• Sub-arcsecond Imaging of the Complex Organic Chemistry in Massive Star-forming Region G10.6-0.4
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- X. Chemical differentiation among the massive cores in G9.62+0.19