Chemistry of massive young stellar objects with a disk-like structure

Abstract

Our goal is to take an inventory of complex molecules in three well-known high-mass protostars for which disks or toroids have been claimed and to study the similarities and differences with a sample of massive YSOs without evidence of such flattened disk-like structures. With a disk-like geometry, UV radiation can escape more readily and potentially affect the ice and gas chemistry on hot-core scales. A partial submillimeter line survey, targeting CH3OH, H2CO, C2H5OH, HCOOCH3, CH3OCH3, CH3CN, HNCO, NH2CHO, C2H5CN, CH2CO, HCOOH, CH3CHO, and CH3CCH, was made toward three massive YSOs with disk-like structures, IRAS20126+4104, IRAS18089-1732, and G31.41+0.31. Rotation temperatures and column densities were determined by the rotation diagram method, as well as by independent spectral modeling. The molecular abundances were compared with previous observations of massive YSOs without evidence of any disk structure, targeting the same molecules with the same settings and using the same analysis method. Consistent with previous studies, different complex organic species have different characteristic rotation temperatures and can be classified either as warm (>100 K) or cold (<100 K). The excitation temperatures and abundance ratios are similar from source to source and no significant difference can be established between the two source types. Acetone, CH3COCH3, is detected for the first time in G31.41+0.31 and IRAS18089-1732. Temperatures and abundances derived from the two analysis methods generally agree within factors of a few. The lack of chemical differentiation between massive YSOs with and without observed disks suggest either that the chemical complexity is already fully established in the ices in the cold prestellar phase or that the material experiences similar physi- cal conditions and UV exposure through outflow cavities during the short embedded lifetime.

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Cited by in corpus (32)

• The ALMA-PILS survey: Isotopic composition of oxygen-containing complex organic molecules toward IRAS 16293-2422B
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• The ALMA-PILS survey: First detections of ethylene oxide, acetone and propanal toward the low-mass protostar IRAS 16293-2422
• The formation of ethylene glycol and other complex organic molecules in star-forming regions
• The ALMA-PILS survey: Complex nitriles towards IRAS 16293--2422
• Complex organic molecules in low-mass protostars on solar system scales -- I. Oxygen-bearing species
• Interstellar formamide (NH${}_2$CHO), a key prebiotic precursor
• The ALMA-PILS survey: Formaldehyde deuteration in warm gas on small scales toward IRAS 16293-2422 B
• Complex organic molecules in low-mass protostars on Solar System scales -- II. Nitrogen-bearing species
• Survey Observations of a Possible Glycine Precursor, Methanimine (CH${}_2$NH)
• Chemical complexity induced by efficient ice evaporation in the Barnard 5 molecular cloud
• The GUAPOS project: G31.41+0.31 Unbiased ALMA sPectral Observational Survey -- I. Isomers of C${}_2$H${}_4$O${}_2$
• CoCCoA: Complex Chemistry in hot Cores with ALMA. Selected oxygen-bearing species
• Complex organic molecules in organic-poor massive young stellar objects
• JWST Observations of Young protoStars (JOYS): overview of program and early results
• A high resolution study of complex organic molecules in hot cores
• Identification of Methyl Isocyanate and Other Complex Organic Molecules in a Hot Molecular Core, G31.41+0.31
• 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
• A Detailed View of the Circumstellar Environment and Disk of the Forming O-star AFGL 4176
• Search for methylamine in high mass hot cores
• X-ray photolysis of CH${}_3$COCH${}_3$ ice: Implications for the radiation effects of compact objects towards astrophysical ices
• Methanol masers reveal the magnetic field of the high-mass protostar IRAS 18089-1732
• An inherited complex organic molecule reservoir in a warm planet-hosting disk
• CoCCoA: Complex Chemistry in hot Cores with ALMA. The chemical evolution of acetone from ice to gas
• Detection of antifreeze molecule ethylene glycol in the hot molecular core G358.93$-$0.03 MM1
• Study of Complex Nitrogen and Oxygen-bearing Molecules toward the High-mass Protostar IRAS 18089$-$1732
• Millimeter-wave spectrum of 2-propanimine
• Parsec scales of carbon chain and complex organic molecules in AFGL 2591 and IRAS 20126
• Molecular complexity on disk-scales uncovered by ALMA: The chemical composition of the high-mass protostar AFGL 4176
• Interrelations between Astrochemistry and Galactic Dynamics
• First detection of methyl formate in the hot molecular core IRAS 18566+0408