The formation of brown dwarfs : Observational properties

How do brown dwarfs (BDs) form? The formation of substellar objects is still under debate, and several mechanisms have been proposed to explain their origin, e.g. gravoturbulent fragmentation, disk fragmentation or the ejection from a multiple system at very early stages of their evolution. In this talk I will review different observational studies focused on understanding the origin of brown dwarfs: I will describe the main properties of the so-called Very Low Luminosity Objects (VeLLOs), the first hydrostatic cores, and some interesting properties of young BDs that can shed light on their formation mechanism