Organic Molecules in the Hot Corinos and Circumstellar Disks of IRAS 16293-2422

Abstract

Using the recently-commissioned Submillimeter Array (SMA), we have detected several complex organic molecules, including (CH3)2O, C2H5OH, C2H5CN, and tentatively CH2CDCN, toward the protostellar hot cores of IRAS 16293-2422 at arcsecond-resolution (~< 400 AU in radius). Vibrationally excited transitions of SO, SO2 and HCN with energy levels up to 1800 K were also observed. In addition to the other organic molecules (HC3N, CH2CO, CH3OH, CH2CHCN and HCOOCH3) previously reported by us (Kuan et al. 2004), these results clearly indicate the existence of a rich organic chemistry in low-mass `hot corinos'. From the observation of optically thin HC15N emission, we conclude I16293A is a rotating circumstellar disk lying along the north-south direction ~10 deg to the east and with an inclination ~30 deg to the sky. We suggest that the observed vibrational SO and SO2 emission may originate from shock waves near or in the circumstellar disks. Between the two cores, we find a strong anticorrelation in emission from C2H5OH and C2H5CN. The relative contribution of gas phase and grain-surface chemistries to the production of the observed complex molecules is discussed. We point out the shortcomings underlying recent claims that all the O-bearing organics are formed on grains. The presence of so many well-known interstellar molecules in solar-type hot corinos strengthens the link between molecular cloud chemistry, the starting materials of protoplanetary disks such as the protosolar nebula, and the composition of comets. Establishing the fine details of this connection is crucial in answering fundamental questions concerning the importance of galactic astrochemistry for astrobiology.

17 pages, 4 figures, to be published in Advances in Space Research

References in corpus (7)

• Does IRAS 16293-2422 have a hot core? Chemical inventory and abundance changes in its protostellar environment
• First detection of triply-deuterated methanol
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• Ingredients for Solar-like Systems: protostar IRAS 16293-2422 B versus comet 67P/Churyumov-Gerasimenko
• Arcsecond-Resolution Submillimeter HCN Imaging of the Binary Protostar IRAS 16293-2422
• Chemistry of massive young stellar objects with a disk-like structure
• ALMA Survey of Orion Planck Galactic Cold Clumps (ALMASOP): A Hot Corino Survey toward Protostellar Cores in the Orion Cloud
• Successive deuteration in low-mass star-forming regions: the case of D${}_2$-methanol (CHD${}_2$OH) in IRAS 16293-2422
• Organic chemistry of low-mass star-forming cores I: 7 mm spectroscopy of Chamaeleon MMS1
• Substructures in the Disk-Forming Region of the Class 0 Low-Mass Protostellar Source IRAS 16293-2422 Source A on a 10 au Scale
• Complex molecules toward low-mass protostars: the Serpens core
• Rotating Motion of the Outflow of IRAS 16293-2422 A1 at its Origin Point near the Protostar