Related papers: The minimum mass for star formation, and the origi…
Searches for companions of brown dwarfs by direct imaging probe mainly 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 report the first characterisation of the individual discs in the intermediate separation binary systems KK Oph and HD 144668 at millimetre wavelengths. In both systems the circum-primary and the circum-secondary discs are detected in the…
The stellar mass distribution in star-forming regions, stellar clusters and associations, the Initial Mass Function (IMF), appears to be invariant across different star-forming environments, and is consistent with the IMF observed in the…
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 develop a semi-analytic model to investigate how accretion onto wide low-mass binary stars can result in a close high-mass binary system. The key ingredient is to allow mass accretion while limiting the gain in angular momentum. We…
Forming stars emit a significant amount of radiation into their natal environment. While the importance of radiation feedback from high-mass stars is widely accepted, radiation has generally been ignored in simulations of low-mass star…
Over the past 25 years, observations have uncovered a large population of free-floating planets (FFPs), whose origins remain debated. Massive FFPs (several Jupiter masses or more) may form via gravitational collapse of molecular clouds,…
The detection of Earth-size exoplanets around low-mass stars -- in stars such as Proxima Centauri and TRAPPIST-1 -- provide an exceptional chance to improve our understanding of the formation of planets around M stars and brown dwarfs. We…
Analysis of APOGEE DR12 stellar radial-velocities by Troup et al. (2016) affirmed the existence of the well-known Brown-Dwarf Desert (BDD). They detected a dearth of spectroscopic binaries (SB) with periods shorter than $\sim 10$ - $30$…
Abridged. A large fraction of stars are found in binary systems. It is therefore important for our understanding of the star formation process, to investigate the fragmentation of dense molecular cores. We study the influence of the…
We have recently presented observational evidence which suggests that the origin of the second generation (G2) stars in globular clusters (GCs) is due to the binary-mediated collision of primordial (G1) low-mass main-sequence (MS) stars.…
Recent direct imaging discoveries suggest a new class of massive, distant planets around A stars. These widely separated giants have been interpreted as signs of planet formation driven by gravitational instability, but the viability of…
Dust grains in low-metallicity star-forming regions may be responsible for the formation of the first low-mass stars. The minimal conditions to activate dust-induced fragmentation require the gas to be pre-enriched above a critical…
Identifying planets around O-type and B-type stars is inherently difficult; the most massive known planet host has a mass of only about $3M_{\odot}$. However, planetary systems which survive the transformation of their host stars into white…
Studies of fundamental parameters of very low-mass objects are indispensable to provide tests of stellar evolution models that are used to derive theoretical masses of brown dwarfs and planets. However, only objects with dynamically…
Recent spacecraft observations exploring solar system properties impact standard paradigms of the formation of stars, planets and comets. We stress the unexpected cloud of microscopic dust resulting from the DEEP IMPACT mission, and the…
We examine the statistics of main-sequence / main-sequence, main-sequence / white-dwarf and white-dwarf / white-dwarf wide binaries at 10^2.5-10^4 AU separations in Gaia data. For binaries containing a white dwarf, we find a complex…
We present the results of a study performed with the goal to investigate whether low-mass pre-main sequence binary stars are formed by multiple fragmentation or via stellar capture. If binaries form preferentially by fragmentation, we…
We describe spectroscopic observations of 21 low-mass (<0.45 M_sun) white dwarfs (WDs) from the Palomar-Green Survey obtained over four years. We use both radial velocities and infrared photometry to identify binary systems, and find that…
We conjecture that brown dwarfs are substellar objects because they have been ejected from small newborn multiple systems which have decayed in dynamical interactions. In this view, brown dwarfs are stellar embryos for which the star…