Chemical and kinematic structure of extremely high-velocity molecular jets in the Serpens Main star-forming region

Abstract

The fastest molecular component to the protostellar outflows -- extremely high-velocity (EHV) molecular jets -- are still puzzling since they are seen only rarely. The first aim is to analyze the interaction between the EHV jet and the slow outflow by comparing their outflow force content. The second aim is to analyze the chemical composition of the different outflow velocity components and to reveal the spatial location of molecules. ALMA 3 mm and 1.3 mm observations of five outflow sources at 130 -- 260 au resolution in the Serpens Main cloud are presented. Observations of CO, SiO, H${}_2$CO and HCN reveal the kinematic and chemical structure of those flows. Three velocity components are distinguished: the slow and the fast wing, and the EHV jet. Out of five sources, three have the EHV component. Comparison of outflow forces reveals that only the EHV jet in the youngest source Ser-emb 8 (N) has enough momentum to power the slow outflow. The SiO abundance is generally enhanced with velocity, while HCN is present in the slow and the fast wing, but disappears in the EHV jet. For Ser-emb 8 (N), HCN and SiO show a bow-shock shaped structure surrounding one of the EHV peaks suggesting sideways ejection creating secondary shocks upon interaction with the surroundings. Also, the SiO abundance in the EHV gas decreases with distance from this protostar, whereas that in the fast wing increases. H${}_2$CO is mostly associated with low-velocity gas but also appears surprisingly in one of the bullets in the Ser-emb~8~(N) EHV jet. The high detection rate suggests that the presence of the EHV jet may be more common than previously expected. The origin and temporal evolution of the abundances of SiO, HCN and H${}_2$CO through high-temperature chemistry are discussed. The data are consistent with a low C/O ratio in the EHV gas versus high C/O ratio in the fast and slow wings.

25 pages, 20 figures, Accepted for publication in the Astronomy & Astrophysics

References in corpus (19)

• MAMBO Mapping of Spitzer c2d Small Clouds and Cores
• The Evolution of Outflow-Envelope Interactions in Low-Mass Protostars
• SiO line emission from C-type shock waves : interstellar jets and outflows
• The Gould's Belt Distances Survey (GOBELINS) I. Trigonometric parallax distances and depth of the Ophiuchus complex
• Seeds of Life in Space (SOLIS) III. Formamide in protostellar shocks: evidence for gas-phase formation
• Warm SiO gas in molecular bullets associated with protostellar outflows
• APEX-CHAMP+ high-J CO observations of low-mass young stellar objects: IV. Mechanical and radiative feedback
• Formation of simple organic molecules in inner T Tauri disks
• ALMA observations of dust polarization and molecular line emission from the Class 0 protostellar source Serpens SMM1
• The ALMA view of the protostellar system HH212 - The wind, the cavity, and the disk
• Shells, jets, and internal working surfaces in the molecular outflow from IRAS 04166+2706
• Outflows, infall and evolution of a sample of embedded low-mass protostars. The William Herschel Line Legacy (WILL) survey
• First image of the L1157 molecular jet by the CALYPSO IRAM-PdBI survey
• [OI]63micron jets in class 0 sources detected by Herschel
• Origin of warm and hot gas emission from low-mass protostars: Herschel-HIFI observations of CO J=16-15. I. Line profiles, physical conditions, and H2O abundance
• Anatomy of the internal bow shocks in the IRAS 04166+2706 protostellar jet
• Water in star-forming regions with Herschel (WISH) V. The physical conditions in low-mass protostellar outflows revealed by multi-transition water observations
• Fast molecular jet from L1157-mm
• The JCMT dense gas survey of the Perseus Molecular Cloud

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• Water in star-forming regions (WISH): Physics and chemistry from clouds to disks as probed by Herschel spectroscopy
• Complex organic molecules in low-mass protostars on solar system scales -- I. Oxygen-bearing species
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• Modeling accretion shocks at the disk-envelope interface -- Sulfur chemistry
• Large-scale CO spiral arms and complex kinematics associated with the T Tauri star RU Lup
• The JCMT BISTRO survey: alignment between outflows and magnetic fields in dense cores/clumps
• A Unified Model for Bipolar Outflows from Young Stars: Kinematic Signatures of Jets, Winds, and Their Magnetic Interplay with the Ambient Toroids
• The prebiotic molecular inventory of Serpens SMM1 I. An investigation of the isomers CH${}_3$NCO and HOCH${}_2$CN
• Dissecting the different components of the modest accretion bursts of the very young protostar HOPS 373
• FAUST XVII: Super deuteration in the planet forming system IRS 63 where the streamer strikes the disk
• A Unified Model for Bipolar Outflows from Young Stars: Apparent Magnetic Jet Acceleration
• Revealing multiple nested molecular outflows with rotating signatures in HH270mms1-A with ALMA
• Protostellar Outflows: a window to the past
• Seeds of Life in Space (SOLIS) VIII. SiO isotopic fractionation and a new insight in the shocks of L1157-B1
• The JCMT Transient Survey: Four Year Summary of Monitoring the Submillimeter Variability of Protostars