Evolution of Mass Outflow in Protostars

Abstract

We have surveyed 84 Class 0, Class I, and flat-spectrum protostars in mid-infrared [Si II], [Fe II] and [S I] line emission, and 11 of these in far-infrared [O I] emission. We use the results to derive their mass outflow rates. Thereby we observe a strong correlation of mass outflow rates with bolometric luminosity, and with the inferred mass accretion rates of the central objects, which continues through the Class 0 range the trend observed in Class II young stellar objects. Along this trend from large to small mass-flow rates, the different classes of young stellar objects lie in the sequence Class 0 -- Class I/flat-spectrum -- Class II, indicating that the trend is an evolutionary sequence in which mass outflow and accretion rates decrease together with increasing age, while maintaining rough proportionality. The survey results include two which are key tests of magnetocentrifugal outflow-acceleration mechanisms: the distribution of the outflow/accretion branching ratio b, and limits on the distribution of outflow speeds. Neither rule out any of the three leading outflow-acceleration, angular-momentum-ejection mechanisms, but they provide some evidence that disk winds and accretion-powered stellar winds (APSWs) operate in many protostars. An upper edge observed in the branching-ratio distribution is consistent with the upper bound of b = 0.6 found in models of APSWs, and a large fraction (0.31) of the sample have branching ratio sufficiently small that only disk winds, launched on scales as large as several AU, have been demonstrated to account for them.

Version submitted to ApJ: 36 pages, 3 tables, 8 figures

References in corpus (11)

• Identifying the Low Luminosity Population of Embedded Protostars in the c2d Observations of Clouds and Cores
• The Herschel Orion Protostar Survey: Spectral Energy Distributions and Fits Using a Grid of Protostellar Models
• Accretion-Powered Stellar Winds II: Numerical Solutions for Stellar Wind Torques
• Molecular Outflows Driven by Low-Mass Protostars. I. Correcting for Underestimates When Measuring Outflow Masses and Dynamical Properties
• Accretion-Powered Stellar Winds III: Spin Equilibrium Solutions
• X-winds in Action
• Stellar and Circumstellar Properties of Class I Protostars
• SMA CO(2-1) Observations of CG30: A Protostellar Binary System with a High-Velocity Quadrupolar Molecular Outflow
• [OI] disk emission in the Taurus star forming region
• Si and Fe depletion in Galactic star-forming regions observed by the Spitzer Space Telescope
• Time-monitoring Observations of Br$\gamma$ Emission from Young Stars

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