Related papers: PPV Chapter - The Formation of Brown Dwarfs
Dust formation in brown dwarf atmospheres is studied by utilising a model for driven turbulence in the mesoscopic scale regime. We apply a pseudo-spectral method where waves are created and superimposed within a limited wavenumber interval.…
A large fraction of brown dwarfs and low-mass H-burning stars may form by gravitational fragmentation of protostellar discs. We explore the conditions for disc fragmentation and we find that they are satisfied when a disc is large enough…
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…
Isolated low-mass stars are formed, in the standard picture, from the collapse of dense cores condensed out of strongly magnetized molecular clouds. The dynamically collapsing inflow traps nearly half of the critical magnetic flux needed…
The formation and evolution of brown dwarfs are currently "hot topics" in cool star research. Latest observations and modeling efforts on disks, accretion, outflows, spatial distribution, and binarity in the context of the formation 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…
Brown dwarfs may have such low masses because they are prematurely ejected from small unstable multiple systems, while the members are still actively building up their masses. We demonstrate that this scenario is consistent with all…
We present a comprehensive Bayesian statistical analysis of brown dwarf companions to investigate the physical mechanisms responsible for the observed ``brown dwarf desert'' -- the notable paucity of brown dwarf companions at orbital…
A gas-grain time dependent chemical code, UCL\_CHEM, has been used to investigate the possibility of using chemical tracers to differentiate between the possible formation mechanisms of brown dwarfs. In this work, we model the formation of…
Context. Most observational studies so far point towards brown dwarfs sharing a similar formation mechanism as the one accepted for low mass stars. However, larger databases and more systematic studies are needed before strong conclusions…
Studying the earliest stages in the birth of stars is crucial for understanding how they form. Brown dwarfs with masses between that of stars and planets are not massive enough to maintain stable hydrogen-burning fusion reactions during…
The first steps toward planet formation involve the coagulation of small microscopic grains into larger and larger pebbles and rocks in gas-rich disks around young stars and brown dwarfs. Observations in the sub-millimeter can trace…
Brown dwarfs, which straddle the mass range between stars and planets, appear to be common both in the solar neighborhood and in star-forming regions. Their ubiquity makes the question of their origin an important one both for our…
In this paper we discuss the nature and the possible formation scenarios of the companion of the brown dwarf 2MASS 1207334-393254. We initially discuss the basic physical properties of this object and conclude that, although from its…
The birth of stars involves not only accretion but also, counter-intuitively, the expulsion of matter in the form of highly supersonic outflows. Although this phenomenon has been seen in young stars, a fundamental question is whether it…
Supersonic turbulence fragments the interstellar medium into dense sheets, filaments, cores and large low density voids. The turbulence is driven on large scales, probably predominantly by supernovae. The scaling properties of supersonic…
Whilst there is a generally accepted evolutionary scheme for the formation of low-mass stars, the analogous processes when moving down in mass to the brown dwarfs regime are not yet well understood. In this first paper we try to build the…
We have carried out 200,000 N-body simulations of three identical stellar embryos with masses from a Chabrier IMF and embedded in a molecular core. The bodies are initially non-hierarchical and undergo chaotic motions, while accreting using…
The onset of planet formation in protoplanetary disks is marked by the growth and crystallization of sub-micron-sized dust grains accompanied by dust settling toward the disk mid-plane. Here we present infrared spectra of disks around brown…
A new model for the formation of Jovian planets is proposed. We consider planets forming at large distances from a protostar (>100 AU) through direct fragmentation of a gas cloud, by the same formation mechanism as wide stellar and brown…