Protostar mass functions in young clusters

Abstract

In an improved model of protostar mass functions (PMFs), protostars gain mass from isothermal cores in turbulent clumps. Their mass accretion rate is similar to Shu accretion at low mass, and to reduced Bondi accretion at high mass. Accretion durations follow a simple expression in which higher-mass protostars accrete for longer times. These times are set by ejections, stellar feedback, and gravitational competition, which terminate accretion and reduce its efficiency. The mass scale is the mass of a critically stable isothermal core. In steady state, the PMF approaches a power law at high mass due to competition between clump accretion and accretion stopping. The power law exponent is the ratio of the time scales of accretion and accretion stopping. The luminosity function (PLF) peaks near 1 L_Sun, due to inefficient accretion of core gas. Models fit observed PLFs in four large embedded clusters. These indicate that their underlying PMFs may be top-heavy compared to the IMF, depending on the model of protostar radius.

accepted by The Astrophysical Journal

References in corpus (12)

• Cold Dark Clouds: The Initial Conditions for Star Formation
• A Spitzer Survey of Young Stellar Clusters within One Kiloparsec of the Sun: Cluster Core Extraction and Basic Structural Analysis
• Analytical theory for the initial mass function: CO clumps and prestellar cores
• The Effects of Radiative Transfer on Low-Mass Star Formation
• Bolocam Survey for 1.1 mm Dust Continuum Emission in the c2d Legacy Clouds. II. Ophiuchus
• The Nature of the Dense Core Population in the Pipe Nebula: Thermal Cores Under Pressure
• An Ammonia Spectral Atlas of Dense Cores in Perseus
• The Different Structures of the Two Classes of Starless Cores
• On the Constancy of the Characteristic Mass of Young Stars
• NH3 Observations of the Infrared Dark Cloud G28.34+0.06
• Clump Lifetimes and the Initial Mass Function
• Mass distributions of stars and cores in young groups and clusters

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