Synthesis of complex organic molecules in soft x-ray irradiated ices

Abstract

We study the chemical evolution of H2O:CO:NH3 ice mixtures irradiated with soft X-rays, in the range 250-1250 eV. We identify many nitrogen-bearing molecules such as e.g., OCN-, NH4+ , HNCO, CH3CN, HCONH2, and NH2COCONH2. Several infrared features are compatible with glycine or its isomers. During the irradiation, we detected through mass spectroscopy many species desorbing the ice. Such findings support either the infrared identifications and reveal less abundant species with not clear infrared features. Among them, m/z = 57 has been ascribed to methyl isocyanate (CH3NCO), a molecule of prebiotic relevance, recently detected in protostellar environments. During the warm up after the irradiation, several infrared features including 2168 cm-1 band of OCN-, 1690 cm-1 band of formamide, and the 1590 cm-1 band associated to three different species, HCOO-, CH3NH2 and NH3+CH2COO survive up to room temperature. Interestingly, many high masses have been also detected. Possible candidates are methyl-formate, (m/z = 60, HCOOCH3), ethanediamide (m/z = 88, NH2COCONH2), and N-acetyl-L-aspartic acid (m=z = 175). This latter species is compatible with the presence of the m/z = 43, 70 and 80 fragments. Photo-desorption of organics is relevant for the detection of such species in the gas-phase of cold environments, where organic synthesis in ice mantles should dominate. We estimate the gas-phase enrichment of some selected species in the light of a protoplanetary disc model around young solar-type stars.

References in corpus (24)

• Observations of the Icy Universe
• Evolution of the Solar Activity over Time and Effects on Planetary Atmospheres: I. High-energy Irradiances (1-1700 A)
• The Spitzer ice legacy: Ice evolution from cores to protostars
• 2018 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules
• The cometary composition of a protoplanetary disk as revealed by complex cyanides
• Molecular Hydrogen Emission from Protoplanetary Disks II. Effects of X-ray Irradiation and Dust Evolution
• Chemical Processes in Protoplanetary Disks II. On the importance of photochemistry and X-ray ionization
• A quantitative analysis of OCN- formation in interstellar ice analogs
• Thermal desorption of circumstellar and cometary ice analogs
• A 3-5$\mu$m VLT spectroscopic survey of embedded young low mass stars II; OCN${}^{-}$
• The census of interstellar complex organic molecules in the Class I hot corino of SVS13-A
• The ALMA-PILS survey: Detection of CH${}_3$NCO toward the low-mass protostar IRAS 16293-2422 and laboratory constraints on its formation
• The Strengths of Near-Infrared Absorption Features Relevant to Interstellar and Planetary Ices
• Radiolysis of ammonia-containing ices by energetic, heavy and highly charged ions inside dense astrophysical environments
• The formation of peptide-like molecules on interstellar dust grains
• H-atom bombardment of CO2, HCOOH and CH3CHO containing ices
• An IR study of pure and ion irradiated frozen formamide
• Detection of CH3SH in protostar IRAS 16293-2422
• Detection of methylisocyanate (CH3NCO) in a solar-type protostar
• Comparison of UV and high-energy ion irradiation of methanol:ammonia ice
• Investigation of HNCO isomers formation in ice mantles by UV and thermal processing: an experimental approach
• CH in absorption in IRAS16293-2422
• Photo-desorption of H2O:CO:NH3 circumstellar ice analogs: Gas-phase enrichment
• On The Photodesorption of CO${}_2$ Ice Analogues: The Formation of Atomic C in The Ice and the Effect of The VUV Emission Spectrume

Cited by in corpus (9)

• LIDA - The Leiden Ice Database for Astrochemistry
• Formation of NH2CHO and CH3CHO upon UV photoprocessing of interstellar ice analogs
• Exploring the link between star and planet formation with Ariel
• The hunt for formamide in interstellar ices: A toolkit of laboratory infrared spectra in astronomically relevant ice mixtures and comparisons to ISO, Spitzer, and JWST observations
• Formation of the simplest amide in molecular clouds: formamide (NH${}_2$CHO) and its derivatives in H${}_2$O-rich and CO-rich interstellar ice analogs upon VUV irradiation
• Photoprocessing of formamide ice: route towards prebiotic chemistry in space
• Optical tweezers in a dusty universe
• Integrated molar absorptivity of mid- and far-infrared spectra of glycine and other selected amino acids
• Interstellar carbonaceous dust erosion induced by X-ray irradiation of water ice in star-forming regions