A discontinuity in the low-mass initial mass function

Abstract

The origin of brown dwarfs (BDs) is still an unsolved mystery. While the standard model describes the formation of BDs and stars in a similar way recent data on the multiplicity properties of stars and BDs show them to have different binary distribution functions. Here we show that proper treatment of these uncovers a discontinuity of the multiplicity-corrected mass distribution in the very-low-mass star (VLMS) and BD mass regime. A continuous IMF can be discarded with extremely high confidence. This suggests that VLMSs and BDs on the one hand, and stars on the other, are two correlated but disjoint populations with different dynamical histories. The analysis presented here suggests that about one BD forms per five stars and that the BD-star binary fraction is about 2%-3% among stellar systems.

14 pages, 11 figures, uses emulateapj.cls. Minor corrections and 1 reference added after being accepted by the ApJ

References in corpus (11)

• Stellar Multiplicity and the IMF: Most Stars Are Single
• Exploring brown dwarf disks: A 1.3 mm survey in Taurus
• The minimum mass for star formation, and the origin of binary brown dwarfs
• A search for binary systems among the nearest L dwarfs
• A Survey for Spectroscopic Binaries Among Very Low-Mass Stars
• The Spatial Distribution of Brown Dwarfs in Taurus
• Multiplicity and Optical Excess Across the Substellar Boundary in Taurus
• New Very Low Mass Binaries in the Taurus Star-Forming Region
• Brown dwarf formation by binary disruption
• Oph 1622-2405: Not a Planetary-Mass Binary
• The spatial distribution of substellar objects in IC348 and the Orion Trapezium Cluster

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