Related papers: Stellar and brown dwarf properties from numerical …
Our first aim is to calculate the minimum mass for Primary Fragmentation in a variety of potential star-formation scenarios, i.e. (i) hierarchical fragmentation of a 3-D medium; (ii) one-shot, 2-D fragmentation of a shock-compressed layer;…
Binary statistics of the latest-type T and Y brown dwarfs are sparse and it is unclear whether the trends seen in the multiplicity properties of their more massive counterparts hold for the very coolest brown dwarfs. We present results from…
We have undertaken a series of hydrodynamic + N-body simulations in order to explore the properties of young stars. Our results suggest that the IMF may be sensitive to environment in its substellar region, with more brown dwarfs being…
We present the results of an ensemble of simulations of the collapse and fragmentation of dense star-forming cores. We show that even with very low levels of turbulence the outcome is usually a binary, or higher-order multiple, system. We…
We investigate the formation of brown dwarfs and very low-mass stars through the gravitational fragmentation of infalling gas into stellar clusters. The gravitational potential of a forming stellar cluster provides the focus that attracts…
In this review, we summarize the observed statistical properties of visual binaries in various young stellar clusters. The binary frequency, orbital period distribution and mass ratio distribution are considered for populations of both…
We have compiled a sample of 16 orbits for very low-mass stellar (<0.1 Msun) and brown dwarf binaries, enabling the first comprehensive study of the eccentricity distribution for such objects. We find that very low-mass binaries span a…
Searches for companions of brown dwarfs by direct imaging mainly probe orbital separations > 3-10 AU. On the other hand, previous radial velocity surveys of brown dwarfs are mainly sensitive to separations smaller than 0.6 AU. It has been…
We review four mechanisms for forming brown dwarfs: (i) turbulent fragmentation (producing very low-mass prestellar cores); (ii) gravitational instabilities in discs; (iii) dynamical ejection of stellar embryos from their placental cores;…
We rehearse the physical and theoretical considerations that define the nature of Brown Dwarfs, in particular the maximum mass for a Brown Dwarf (set by the Hydrogen-Burning Limit) and the minimum mass for a Brown Dwarf (set by the Opacity…
The observational properties of brown dwarfs pose challenges to the theory of star formation. Because their mass is much smaller than the typical Jeans mass of interstellar clouds, brown dwarfs are most likely formed through secondary…
We examine the spatial distribution of brown dwarfs produced by the decay of small-N stellar systems as expected from the embryo ejection scenario. We model a cluster of several hundred stars grouped into 'cores' of a few stars/brown…
Although many models have been proposed, the physical mechanisms responsible for the formation of low-mass brown dwarfs are poorly understood. The multiplicity properties and minimum mass of the brown-dwarf mass function provide critical…
We have used Monte Carlo simulation techniques and published radial velocity surveys to constrain the frequency of very low-mass star (VLMS) and brown dwarf (BD) binary systems and their separation (a) distribution. Gaussian models for the…
The observational properties of brown dwarfs pose challenges to the theory of star formation. Because their mass is much smaller than the typical Jeans mass of interstellar clouds, brown dwarfs are most likely formed through secondary…
We present an analytical method for constraining the substellar initial mass function in globular clusters, based on the observed frequency of transit events. Globular clusters typically have very high stellar densities where close…
It is estimated that ~60% of all stars (including brown dwarfs) have masses below 0.2Msun. Currently, there is no consensus on how these objects form. I will briefly review the four main theories for the formation of low-mass objects:…
These lectures attempt to expose the most important ideas, which have been proposed to explain the formation of stars with particular emphasis on the formation of brown dwarfs and low-mass stars. We first describe the important physical…
The discovery of large numbers of young low-mass stars and brown dwarfs over the last decade has made it possible to investigate star formation and early evolution in a previously unexplored mass regime. In this review, we begin by…
In this review, we examine the successes and weaknesses of modern low-mass star and brown dwarf theory.(1) We first focus on the mechanical (equation of state) and thermal (atmosphere) properties and on the evolution. We then examine the…