Diversity of chemistry and excitation conditions in the high-mass star forming complex W33

Abstract

The object W33 is a giant molecular cloud that contains star forming regions at various evolutionary stages from quiescent clumps to developed H II regions. Since its star forming regions are located at the same distance and the primary material of the birth clouds is probably similar, we conducted a comparative chemical study to trace the chemical footprint of the different phases of evolution. We observed six clumps in W33 with the Atacama Pathfinder Experiment (APEX) telescope at 280 GHz and the Submillimeter Array (SMA) at 230 GHz. We detected 27 transitions of 10 different molecules in the APEX data and 52 transitions of 16 different molecules in the SMA data. The chemistry on scales larger than $\sim$0.2 pc, which are traced by the APEX data, becomes more complex and diverse the more evolved the star forming region is. On smaller scales traced by the SMA data, the chemical complexity and diversity increase up to the hot core stage. In the H II region phase, the SMA spectra resemble the spectra of the protostellar phase. Either these more complex molecules are destroyed or their emission is not compact enough to be detected with the SMA. Synthetic spectra modelling of the H${}_2$CO transitions, as detected with the APEX telescope, shows that both a warm and a cold component are needed to obtain a good fit to the emission for all sources except for W33 Main1. The temperatures and column densities of the two components increase during the evolution of the star forming regions. The integrated intensity ratios N${}_2$H${}^{+}$(3$-$2)/CS(6$-$5) and N${}_2$H${}^{+}$(3$-$2)/H${}_2$CO(4${}_{2,2}$$-$3${}_{2,1}$) show clear trends as a function of evolutionary stage, luminosity, luminosity-to-mass ratio, and H${}_2$ peak column density of the clumps and might be usable as chemical clocks.

66 pages, 28 figures, 8 tables, accepted for publication at A&A

References in corpus (11)

• Theory of Star Formation
• Cold Dark Clouds: The Initial Conditions for Star Formation
• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• Testing grain-surface chemistry in massive hot-core regions
• Discovery of 35 New Supernova Remnants in the Inner Galaxy
• Multi-wavelength observations of Southern Hot Molecular Cores traced by methanol masers - I. Ammonia and 24 GHz Continuum Data
• A Molecular Line Observation toward Massive Clumps Associated with Infrared Dark Clouds
• The RMS Survey: ${}^{13}$CO observations of candidate massive YSOs in the northern Galactic plane
• Chemical Diversity in High-Mass Star Formation
• SiO and CH3CCH abundances and dust emission in high-mass star-forming cores
• Star formation in a clustered environment around the UCHII region in IRAS 20293+3952

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• Kinetic temperature of massive star forming molecular clumps measured with formaldehyde
• Kinetic temperature of massive star-forming molecular clumps measured with formaldehyde. III. The Orion Molecular Cloud 1
• Kinetic temperature of massive star forming molecular clumps measured with formaldehyde. II. The Large Magellanic Cloud
• The ALMA Survey of 70 $\mu \mathrm{m}$ Dark High-mass Clumps in Early Stages (ASHES). VII: Chemistry of Embedded Dense Cores
• 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
• Massive Stars in the W33 Giant Molecular Complex
• ALMA-IMF. VII. First release of the full spectral line cubes: Core kinematics traced by DCN J=(3-2)
• Kinetic temperature of massive star-forming molecular clumps measured with formaldehyde IV. The ALMA view of N113 and N159W in the LMC
• VLA Survey of Dense Gas in Extended Green Objects: Prevalence of 25 GHz Methanol Masers
• Kinematics and star formation toward W33: a central hub as a hub--filament system
• ALMA-IMF X -- The core population in the evolved W33-Main (G012.80) protocluster
• A multiwavelength study of the W33 Main ultracompact HII region
• A global view on star formation: The GLOSTAR Galactic plane survey. IX. Radio Source Catalog III: 2<l<28, 36<l<40, 56<l<60 and |b|<1, VLA B-configuration
• Formation of hub-filament structure triggered by cloud-cloud collision in W33 complex
• Uncovering distinct environments in an extended physical system around the W33 complex
• Simulated observations of star formation regions: infrared evolution of globally collapsing clouds
• Observations of multiple NH${}_3$ transitions in W33
• SOFIA/GREAT observations of OD and OH rotational lines towards high-mass star forming regions
• Chemical Evolution of HC3N in Dense Molecular Clouds
• Imaging Molecular Outflow in Massive Star-forming Regions with HNCO Lines
• Massive Stars in Molecular Clouds Rich in High-energy Sources: The Bridge of G332.809-0.132 and CS 78 in NGC 6334
• ALMA-IMF VIII -- Combination of Interferometric Continuum Images with Single-Dish Surveys and Structural Analysis of Six Protoclusters
• KAgoshima Galactic Object survey with Nobeyama 45-metre telescope by Mapping in Ammonia lines (KAGONMA): Star formation feedback on dense molecular gas in the W33 complex