相关论文: Brown dwarf formation by binary disruption

We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semi-major axes relative to most near-Earth and Main Belt asteroid systems. Confirmed members have rapidly…

This review summarises recent observational results regarding the evolution of angular momentum and disks in brown dwarfs. The observations clearly show that brown dwarfs beyond ages of 10 Myr are exclusively fast rotators and do not spin…

Many hot subdwarf B stars (sdBs) are in close binaries, and the favored formation channels for subdwarfs rely on mass transfer in a binary system to strip a core He burning star of its envelope. However, these channels cannot account for…

Stars rarely form in isolation. Nearly half of the stars in the Milky Way have a companion, and this fraction increases in star-forming regions. However, why some dense cores and filaments form bound pairs while others form single stars…

We explore two ways in which objects of planetary masses can form. One is in disk systems like the solar system. The other is in dense clusters where stars and brown dwarfs form. We do not yet have the instrumental accuracy to detect…

Low mass white dwarfs are the remnants of disrupted red giant stars in binary millisecond pulsars and other exotic binary star systems. Some low mass white dwarfs cool rapidly, while others stay bright for millions of years due to stable…

Debris disc analysis and modelling provide crucial information about the structure and the processes at play in extrasolar planetary systems. In binary systems, this issue is more complex because the disc should in addition respond to the…

Multiplicity is a key statistic for understanding the formation of very low mass (VLM) stars and brown dwarfs. Currently, the separation distribution of VLM binaries remains poorly constrained at small separations (<1 AU), leading to…

Be stars are rapidly rotating B type stars. The origin of their rapid rotation is not certain, but binary interaction remains to be a possibility. In this work we investigate the formation of Be stars resulting from mass transfer in…

The formation of massive stars is one of the major unsolved problems in stellar astrophysics. However, only few if any of these are found as single stars, on average massive stars have more than one companion. Many of them are born in dense…

Volume complete sky surveys provide evidence for a binary origin for the formation of isolated white dwarfs with magnetic fields in excess of a MegaGauss. Interestingly, not a single high-field magnetic white dwarf has been found in a…

We present ALMA continuum and spectral line data at 0.89 mm and 3.2 mm for three disks surrounding young brown dwarfs and very low mass stars in the Taurus star forming region. Dust thermal emission is detected and spatially resolved for…

We report on nine wide common proper motion systems containing late-type M, L, or T companions. We confirm six previously reported companions, and identify three new systems. The ages of these systems are determined using diagnostics for…

We present the results of numerical simulations which show the formation of blue compact dwarf (BCD) galaxies from merging between very gas-rich dwarfs with extended HI gas disks. We show that dwarf-dwarf merging can trigger central…

The formation of massive stars in close binary systems is complicated due to their high radiation pressure, the crowded environment and the expected minimum separation for fragmentation being many times greater than the orbital separation.…

It has long been accepted that a possible mechanism for explaining the existence of magnetic white dwarfs is the merger of a binary white dwarf system, as there are viable mechanisms for producing sustainable magnetic fields within the…

Self-gravitating protostellar discs are unstable to fragmentation if the gas can cool on a time scale that is short compared to the orbital period. We use a combination of hydrodynamic simulations and N-body orbit integrations to study the…

We present a new dynamical scenario for the formation of short-period binary millisecond pulsars in globular clusters. Our work is motivated by the recent observations of 20 radio pulsars in 47 Tuc. In a dense cluster such as 47 Tuc, most…

Direct imaging searches have revealed many very low-mass objects, including a small number of planetary mass objects, as wide-orbit companions to young stars. The formation mechanism of these objects remains uncertain. In this paper we…

We review recent theoretical progress aimed at understanding the formation and the early stages of evolution of giant planets, low-mass stars and brown dwarfs. Calculations coupling giant planet formation, within a modern version of the…