How do brown dwarves form?

Snowhite and the ω dwarves

If (I,<) is a linearly ordered set, and (di)i∈I is a sequence of dwarves indexed by I, we say that a property P (x) holds eventually if there exists i0 ∈ I such that for all j > i0 we have P (dj). Let (di)i∈I be a sequence of dwarves, all distinct. The Devil puts a hat on the head of each dwarf. Each dwarf cannot see the colour of his own hat, but receives some additional information (depending...

Simulating star formation in molecular cloud cores I. The influence of low levels of turbulence on fragmentation and multiplicity

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 take as the initial conditions for these simulations a typical low-mass core, based on the average properties of a large sample of observed cores. All the sim...

The Formation of Free-Floating Brown Dwarves and Planetary-Mass Objects by Photo-Erosion of Prestellar Cores

We explore the possibility that, in the vicinity of an OB star, a prestellar core which would otherwise have formed an intermediate or low-mass star may form a free-floating brown dwarf or planetary-mass object, because the outer layers of the core are eroded by the ionizing radiation from the OB star before they can accrete onto the protostar at the centre of the core. The masses of objects fo...

PEGASE: a DARWIN/TPF pathfinder

The space mission PEGASE, proposed to the CNES (Centre National d’Etudes Spatiales = French Space Agency) in the framework of its call for scientific proposals : “formation flying missions”, is a 2-aperture interferometer, composed by 3 free flying satellites (2 siderostats and 1 beam combiner), allowing baselines from 50 to 500 m in both nulling and visibility modes. With an angular resolution...

Made in God’s Image: Velazquez’s Portraits of Dwarves