On the Origin of Stellar Masses

Abstract

It has been a longstanding problem to determine, as far as possible, the characteristic masses of stars in terms of fundamental constants; the almost complete invariance of this mass as a function of the star-forming environment suggests that this should be possible. Here I provide such a calculation. The typical stellar mass is set by the characteristic fragment mass in a star-forming cloud, which depends on the cloud's density and temperature structure. Except in the very early universe, the latter is determined mainly by the radiation released as matter falls onto seed protostars. The energy yield from this process is ultimately set by the properties of deuterium burning in protostellar cores, which determines the stars' radii. I show that it is possible to combine these considerations to compute a characteristic stellar mass almost entirely in terms of fundamental constants, with an extremely weak residual dependence on the interstellar pressure and metallicity. This result not only explains the invariance of stellar masses, it resolves a second mystery: why fragmentation of a cold, low-density interstellar cloud, a process with no obvious dependence on the properties of nuclear reactions, happens to select a stellar mass scale such that stellar cores can ignite hydrogen. Finally, the weak residual dependence on the interstellar pressure and metallicity may explain recent observational hints of a smaller characteristic mass in the high pressure, high metallicity cores of giant elliptical galaxies.

7 pages, 5 figures, emulateapj format. Accepted to ApJ

References in corpus (21)

• Slow Star Formation in Dense Gas: Evidence and Implications
• Analytical theory for the initial mass function: CO clumps and prestellar cores
• The Resolved Properties of Extragalactic Giant Molecular Clouds
• Radiation-Hydrodynamic Simulations of Collapse and Fragmentation in Massive Protostellar Cores
• A Minimum Column Density of 1 g cm^-2 for Massive Star Formation
• The Mass Distribution and Lifetime of Prestellar Cores in Perseus, Serpens, and Ophiuchus
• The Effects of Radiative Transfer on Low-Mass Star Formation
• The Importance of Radiative Feedback for the Stellar Initial Mass Function
• The Nature of the Dense Core Population in the Pipe Nebula: Thermal Cores Under Pressure
• An Ammonia Spectral Atlas of Dense Cores in Perseus
• WFCAM, Spitzer-IRAC and SCUBA observations of the massive star forming region DR21/W75: I. The collimated molecular jets
• Dynamics of Dense Cores in the Perseus Molecular Cloud
• Intermediate to low-mass stellar content of Westerlund 1
• Radiation Feedback and Fragmentation in Massive Protostellar Cores
• On the Constancy of the Characteristic Mass of Young Stars
• Stars In Other Universes: Stellar structure with different fundamental constants
• Protostar Formation in Supersonic Flows: Growth and Collapse of Spherical Cores
• The Kinematics of Molecular Cloud Cores in the Presence of Driven and Decaying Turbulence: Comparisons with Observations
• Metallicity and the Universality of the IMF
• The impact of X-rays on molecular cloud fragmentation and the IMF
• Far-Infrared Spectral Energy Distributions and Photometric Redshifts of Dusty Galaxies

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