FAUST II. Discovery of a Secondary Outflow in IRAS 15398-3359: Variability in Outflow Direction during the Earliest Stage of Star Formation?

Abstract

We have observed the very low-mass Class 0 protostar IRAS 15398-3359 at scales ranging from 50 au to 1800 au, as part of the ALMA Large Program FAUST. We uncover a linear feature, visible in H2CO, SO, and C18O line emission, which extends from the source along a direction almost perpendicular to the known active outflow. Molecular line emission from H2CO, SO, SiO, and CH3OH further reveals an arc-like structure connected to the outer end of the linear feature and separated from the protostar, IRAS 15398-3359, by 1200 au. The arc-like structure is blue-shifted with respect to the systemic velocity. A velocity gradient of 1.2 km/s over 1200 au along the linear feature seen in the H2CO emission connects the protostar and the arc-like structure kinematically. SO, SiO, and CH3OH are known to trace shocks, and we interpret the arc-like structure as a relic shock region produced by an outflow previously launched by IRAS 15398-3359. The velocity gradient along the linear structure can be explained as relic outflow motion. The origins of the newly observed arc-like structure and extended linear feature are discussed in relation to turbulent motions within the protostellar core and episodic accretion events during the earliest stage of protostellar evolution.

References in corpus (70)

• A computer program for fast non-LTE analysis of interstellar line spectra
• The Cologne Database for Molecular Spectroscopy, CDMS, in the Virtual Atomic and Molecular Data Centre, VAMDC
• Dense Cores in Dark Clouds. XIV. N2H+(1-0) maps of dense cloud cores
• Rotational quenching of CO due to H${}_2$ collisions
• The VLA Nascent Disk and Multiplicity Survey of Perseus Protostars (VANDAM). II. Multiplicity of Protostars in the Perseus Molecular Cloud
• Water in star-forming regions with Herschel (WISH): II. Evolution of 557 GHz 110-101 emission in low-mass protostars
• A Triple Protostar System Formed via Fragmentation of a Gravitationally Unstable Disk
• Parametrization of C-shocks. Evolution of the Sputtering of Grains
• A protostellar system fed by a streamer of 10,500 au length
• Signs of Early-Stage Disk Growth Revealed with ALMA
• Hydrodynamical Simulations of Jet- and Wind-driven Protostellar Outflows
• Directions of Outflows, Disks, Magnetic Fields, and Rotation of YSOs in Collapsing Molecular Cloud Cores
• A recent accretion burst in the low-mass protostar IRAS 15398-3359: ALMA imaging of its related chemistry
• Decoupling of Magnetic Fields in Collapsing Protostellar Envelopes and Disk Formation and Fragmentation
• Rotational quenching of H2CO by molecular hydrogen: cross-sections, rates, pressure broadening
• The CHESS chemical Herschel surveys of star forming regions: Peering into the protostellar shock L1157-B1. I. Shock chemical complexity
• Extreme Active Molecular Jets in L1448C
• APEX-CHAMP+ high-J CO observations of low-mass young stellar objects: IV. Mechanical and radiative feedback
• SiO J=5--4 in the HH211 Protostellar Jet Imaged with the SMA
• Distances and Kinematics of Gould Belt Star-Forming Regions with Gaia DR2 results
• ALMA Observations of the HH 46/47 Molecular Outflow
• The observed chemical structure of L1544
• The role of magnetic fields in the formation of protostellar discs
• The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Perseus Protostars. VI. Characterizing the Formation Mechanism for Close Multiple Systems
• A Substellar-Mass Protostar and its Outflow of IRAS 15398-3359 Revealed by Subarcsecond-Resolution Observations of H${}_2$CO and CCH
• Circumstellar disks and outflows in turbulent molecular cloud cores: possible formation mechanism for misaligned systems
• Molecular outflow launched beyond the disk edge
• Silicon-bearing molecules in the shock L1157-B1: first detection of SiS around a Sun-like protostar
• Grain Evolution across the Shocks in the L1448-mm Outflow
• ALMA observations of a high-density core in Taurus: dynamical gas interaction at the possible site of a multiple star formation
• HiRes Deconvolved Spitzer Images of 89 Protostellar Jets and Outflows: New Data on Evolution of Outflow Morphology
• The VLA Nascent Disk And Multiplicity (VANDAM) Survey of Perseus Protostars. Resolving the Sub-Arcsecond Binary System in NGC 1333 IRAS2A
• Sulphur chemistry and molecular shocks: the case of NGC1333-IRAS2
• Angular momentum profiles of Class 0 protostellar envelopes
• The First Two Thousand Years of Star Formation
• Orbital and mass constraints of the young binary system IRAS 16293-2422 A
• Tracing the shock precursors in the L1448-mm/IRS3 outflows
• The Effect of Misalignment between Rotation Axis and Magnetic Field on Circumstellar Disk
• Dense and warm molecular gas in the envelopes and outflows of southern low-mass protostars
• Recent star formation in the Lupus clouds as seen by Herschel
• Seeds of Life in Space (SOLIS) V. Methanol and acetaldehyde in the protostellar jet-driven shocks L1157-B0 and B1
• On the accuracy of the ALMA flux calibration in the time domain and across spectral windows
• Misalignment of Magnetic Fields, Outflows and Discs in Star-forming Clouds
• ALMA Observations of the IRDC Clump G34.43+00.24 MM3: Hot Core and Molecular Outflows
• The Co-evolution of Disk and Star in Embedded Stages: The Case of the Very Low-mass Protostar
• Seeds of Life in Space (SOLIS). III. Zooming into the methanol peak of the pre-stellar core L1544
• The Formation Conditions of the Wide Binary Class 0 Protostars within BHR 71
• Probing Episodic Accretion in Very Low Luminosity Objects
• Submillimeter spectroscopy of H${}_2$C${}^{17}$O and a revisit of the rotational spectra of H${}_2$C${}^{18}$O and H${}_2$C${}^{16}$O
• The ALMA-PILS survey: Gas dynamics in IRAS 16293$-$2422 and the connection between its two protostars
• Dynamics of a Massive Binary at Birth
• Water around IRAS15398-3359 observed with ALMA
• A young bipolar outflow from IRAS 15398-3359
• ALMA observations of the protostellar disk around the VeLLO IRAS 16253-2429
• An Origin for the Angular Momentum of Molecular Cloud Cores: a Prediction from Filament Fragmentation
• On the evolution of the molecular line profiles induced by the propagation of C-shock waves
• Impacts of pure shocks in the BHR71 bipolar outflow
• Magnetic field and early evolution of circumstellar disks
• The role of SiO as a tracer of past star-formation events: The case of the high-mass protocluster NGC 2264-C
• ALMA Reveals A Collision Between Protostellar Outflows in BHR71
• Large-Scale CO Maps of the Lupus Molecular Cloud Complex
• Squeezed between shells? On the origin of the Lupus I molecular cloud. APEX/LABOCA, Herschel, and Planck observations
• The magnetic properties of the protostellar core IRAS 15398-3359
• Seeds of Life in Space SOLIS. IX. Chemical segregation of $\mathrm{S}{\mathrm{O}}_2$ and SO toward the low-mass protostellar shocked region of L1157
• Molecular Distributions of the Protostellar Envelope and the Outflow of IRAS 15398-3359: Principal Component Analysis
• Revised SED of the triple protostellar system VLA 1623-2417
• The dynamically young outflow of the Class 0 protostar Cha-MMS1
• Formation of the Unequal-Mass Binary Protostars in L1551 NE by Rotationally-Driven Fragmentation
• Seeds of Life in Space (SOLIS).VII. Discovery of a cold dense methanol blob toward the L1521F VeLLO system
• Discovery of Striking Difference of Molecular-Emission-Line Richness in the Potential Proto-Binary System NGC 2264 CMM3

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• Dissecting the different components of the modest accretion bursts of the very young protostar HOPS 373
• Chemical and Physical Characterization of the Isolated Protostellar Source CB68: FAUST. IV
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• FAUST VII. Detection of A Hot Corino in the Prototypical Warm Carbon-Chain Chemistry Source IRAS 15398-3359
• Cloudlet Capture Model for Asymmetric Molecular Emission Lines Observed in TMC-1A with ALMA
• Origin and Evolution of Angular Momentum of Class II Disks
• FAUST XXVI. The dust opacity spectral indices of protostellar envelopes bridge the gap between interstellar medium and disks
• Synthetic Observations of the Infalling Rotating Envelope: Links between the Physical Structure and Observational Features
• Episodicity in accretion-ejection processes associated with IRAS 15398-3359
• FAUST XXV. A potential new molecular outflow in [BHB2007] 11
• The JCMT Transient Survey: Four Year Summary of Monitoring the Submillimeter Variability of Protostars