High Angular Resolution, Sensitive CS J=2-1 and J=3-2 Imaging of the Protostar L1551 NE: Evidence for Outflow-Triggered Star Formation ?

Abstract

High angular resolution and sensitive aperture synthesis observations of CS ($J=2-1$) and CS ($J=3-2$) emissions toward L1551 NE, the second brightest protostar in the Taurus Molecular Cloud, made with the Nobeyama Millimeter Array are presented. L1551 NE is categorized as a class 0 object deeply embedded in the red-shifted outflow lobe of L1551 IRS 5. Previous studies of the L1551 NE region in CS emission revealed the presence of shell-like components open toward L1551 IRS 5, which seem to trace low-velocity shocks in the swept-up shell driven by the outflow from L1551 IRS 5. In this study, significant CS emission around L1551 NE was detected at the eastern tip of the swept-up shell from $V_{\mathrm{lsr}}$ = 5.3 km s${}^{-1}$ to 10.1 km s${}^{-1}$, and the total mass of the dense gas is estimated to be 0.18 $\pm$ 0.02 $M_{\odot }$. Additionally, the following new structures were successfully revealed: a compact disklike component with a size of $\approx$ 1000 AU just at L1551 NE, an arc-shaped structure around L1551 NE, open toward L1551 NE, with a size of $\sim 5000$ AU, i.e., a bow shock, and a distinct velocity gradient of the dense gas, i.e., deceleration along the outflow axis of L1551 IRS 5. These features suggest that the CS emission traces the post-shocked region where the dense gas associated with L1551 NE and the swept-up shell of the outflow from L1551 IRS 5 interact. Since the age of L1551 NE is comparable to the timescale of the interaction, it is plausible that the formation of L1551 NE was induced by the outflow impact. The compact structure of L1551 NE with a tiny envelope was also revealed, suggesting that the outer envelope of L1551 NE has been blown off by the outflow from L1551 IRS 5.

29 pages, 12 figures, Accepted for Publication in the Astrophysical Journal

References in corpus (2)

• Unveiling the Circumstellar Envelope and Disk: A Sub-Arcsecond Survey of Circumstellar Structures
• L1551NE - Discovery of a Binary Companion

Cited by in corpus (20)

• A Keplerian Circumbinary Disk around the Protobinary System L1551 NE
• 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
• Angular Momentum Exchange by Gravitational Torques and Infall in the Circumbinary Disk of the Protostellar System L1551 NE
• Active-Region Tilt Angles: Magnetic Versus White-Light Determinations of Joy's Law
• A Spitzer Five-Band Analysis of the Jupiter-Sized Planet TrES-1
• Triggering Collapse of the Presolar Dense Cloud Core and Injecting Short-Lived Radioisotopes with a Shock Wave. I. Varied Shock Speeds
• New Panoramic View of ${}^{12}$CO and 1.1 mm Continuum Emission in the Orion A Molecular Cloud. I. Survey Overview and Possible External Triggers of Star Formation
• Star formation in a clustered environment around the UCHII region in IRAS 20293+3952
• A Case Study of Low-Mass Star Formation
• N2H+ Observations of Molecular Cloud Cores in Taurus
• Entrainment Mechanisms for Outflows in the L1551 Star-Forming Region
• Star Formation Under the Outflow: The Discovery of a Non-Thermal Jet from OMC-2 FIR 3 and its Relationship to the Deeply Embedded FIR 4 Protostar
• Millimeter- and Submillimeter-Wave Observations of the OMC-2/3 region. IV Interaction between the Outflow and the Dense Gas in the Cluster Forming Region of OMC-2 FIR 6
• Low-mass protostars and dense cores in different evolutionary stages in IRAS 00213+6530
• ASTE Submillimeter Observations of a Young Stellar Object Condensation in Cederblad 110
• Skewed Distributions and Opposite Velocity Gradients of Submillimeter Molecular Lines in Low-Mass Protostellar Envelopes
• Nobeyama 45-m Mapping Observations toward Orion A. III. Multi-Line Observations toward an Outflow-shocked Region, OMC-2 FIR
• Dispersing Envelope around the Keplerian Circumbinary Disk in L1551 NE and its Implications for the Binary Growth
• The interaction of hydrodynamic shocks with self-gravitating clouds
• Interferometric observations of nitrogen-bearing molecular species in the star-forming core ahead of HH 80N