Looking for evidence of high-mass star formation at core scale in a massive molecular clump

Abstract

We present a comprehensive physical and chemical study of the fragmentation and star formation activity towards the massive clump AGAL G338.9188+0.5494 harbouring the extended green object EGO 338.92+0.55(b). The presence of an EGO embedded in a massive clump, suggests, at clump scale, that high-mass star formation is occurring. The main goal of this work is to find evidence of such high-mass star formation, but at core scale. Using mm observations of continuum and lines obtained from the ALMA database at Bands 6 and 7, we study the substructure of the massive clump. The angular resolution of the data is about 0.5'', which allow us to resolve structures of about 0.01pc ($\sim$ 2000 au) at the distance of 4.4 kpc. The continuum emission at 340 GHz reveals that the molecular clump is fragmented in five cores, labeled from C1 to C5. The ${}^{12}$CO J=3--2 emission shows the presence of molecular outflows related to three of them. The analysis of the CH${}_3$CN and CH${}_3$CCH emissions suggests temperatures of about 340 and 72~K, respectively, for C1, showing that the methyl cyanide would trace a gas layer closer to the protostar than the methyl acetylene. The obtained mass of core C1 ranges from 3 to 10 M${}_{\odot }$. We found that the discovered molecular outflow arising from core C1 should be the main responsible for the 4.5 $\mu$m extended emission. The average mass and energy of such a molecular outflow is about 0.5 M${}_{\odot }$~and $10^{46}$~erg, respectively, which suggest that 10 M${}_{\odot }$ is the most likely mass value for core C1. Additionally we found that the region is chemically very rich with several complex molecular species. Particularly, from the analysis of the CN emission we found strong evidence that such a radical is indirectly tracing the molecular outflows, more precisely the border of the cavity walls carved out by such outflows.

Accepted for publication in A&A (July 5, 2023)

References in corpus (35)

• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• A Catalog of Extended Green Objects (EGOs) in the GLIMPSE Survey: A new sample of massive young stellar object outflow candidates
• The cometary composition of a protoplanetary disk as revealed by complex cyanides
• Shedding light on the formation of the pre-biotic molecule formamide with ASAI
• Seeds Of Life In Space (SOLIS): The organic composition diversity at 300--1000 au scale in Solar-type star forming regions
• ATLASGAL - Kinematic distances and the dense gas mass distribution of the inner Galaxy
• VLT K-band spectroscopy of massive young stellar objects in (ultra-)compact HII regions
• Millimeter- and Submillimeter-Wave Observations of the OMC-2/3 Region. II. Observational Evidence for Outflow-Triggered Star Formation in the OMC-2 FIR 3/4 Region
• Evolutionary study of complex organic molecules in high-mass star-forming regions
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- XV. Steady Accretion from Global Collapse to Core Feeding in Massive Hub-filament System SDC335
• The ALMA Survey of 70 $\mu \mathrm{m}$ Dark High-mass Clumps in Early Stages (ASHES). II: Molecular Outflows in the Extreme Early Stages of Protocluster Formation
• The Physical and chemical structure of Sagittarius B2 -- IV. Converging filaments in the high-mass cluster forming region Sgr B2(N)
• Massive and low-mass protostars in massive "starless" cores
• Star formation in a clustered environment around the UCHII region in IRAS 20293+3952
• ALMA observations of water deuteration: A physical diagnostic of the formation of protostars
• 13C Isotopic Fractionation of HC3N in Star-Forming Regions -Low-Mass Star Forming Region L1527 and High-Mass Star Forming Region G28.28-0.36-
• Resolving desorption of complex organic molecules in a hot core: Transition from non-thermal to thermal desorption or two-step thermal desorption?
• Methyl cyanide (CH3CN) and propyne (CH3CCH) in the low mass protostar IRAS 16293-2422
• Multi-scale view of star formation in IRAS 21078+5211: From clump fragmentation to disk wind
• The ALMA-PILS survey: propyne (CH${}_3$CCH) in IRAS 16293$-$2422
• ALMA observations of the Th 28 protostellar disk - A new example of counter-rotation between disk and optical jet
• Galactic interstellar sulfur isotopes: A radial ${}^{32}$S$/$${}^{34}$S gradient?
• Modeling chemistry during star formation: Water deuteration in dynamic star-forming regions
• ALMA-IMF IV -- A comparative study of the main hot cores in W43-MM1: detection, temperature and molecular composition
• ALMA Fragmented Source Catalogue in Orion (FraSCO) I. Outflow interaction within an embedded cluster in OMC-2/FIR3, FIR4, and FIR5
• ATOMS: ALMA Three-millimeter Observations of Massive Star-forming regions -- VI. On the formation of the "L" type filament in G286.21+0.17
• ALMA Observations of the massive molecular outflow G331.512-0.103 II: physical properties, kinematics, and geometry modeling
• Near-IR imaging towards a puzzling YSO precessing jet
• Cyano radical emission at small spatial scales towards massive protostars
• Multiple molecular outflows and fragmentation in the IRDC core G34.43+00.24 MM1
• ALMA observations of two massive and dense MALT90 clumps
• Interstellar Complex Organic Molecules in SiO-traced massive outflows
• Spectral-line Survey of the Region of Massive Star Formation W51e1/e2 in the 4 mm Wavelength Range
• Analysis of Low Excitation HDO Transitions Toward the High-Mass Star-forming Regions G34.26+0.15, W51e${}_1$/e${}_2$, and W49N
• Unveiling the substructure of the massive clump AGAL G035.1330$-$00.7450

Cited by in corpus (2)

• Revisiting G29.862-0.0044: a jet cavity disrupted by an outflow in a likely young stellar object wide binary system
• Unveiling the collision between molecular outflows: observational evidence and hydrodynamic simulations