相关论文: Brown dwarf populations in open clusters

We present the stellar and substellar mass function of the open cluster IC2391, plus its radial dependence, and use this to put constraints on the formation mechanism of brown dwarfs. Our multiband optical and infrared photometric survey…

Metal pollution in white dwarf atmospheres is likely to be a signature of remnant planetary systems. Most explanations for this pollution predict a sharp decrease in the number of polluted systems with white dwarf cooling age. Observations…

For understanding the process of star formation it is essential to know how many stars are formed as singles or in multiple systems, as a function of environment and binary parameters. This requires a characterization of the primordial…

(abridged) We use newly available empirical binary fractions for globular clusters to carry out a direct test of the binary evolution hypothesis, and of collisional channels that involve binary stars. More specifically, using the previously…

The dynamics of a close binary system of globular clusters is considered. It is shown that the star transfer process from one of the components to the other should lead to the decrease of dimension of the first cluster with simultaneous…

We used HST/WFC3 observations of a sample of 26 nearby ($\le$20 pc) mid to late T dwarfs to search for cooler companions and measure the multiplicity statistics of brown dwarfs. Tightly-separated companions were searched for using a…

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…

Very low-mass binaries (VLMBs), with system masses <0.2 Msun appear to have very different properties to stellar binaries. This has led to the suggestion that VLMBs form a distinct and different population. As most stars are born in…

(abridged) We present the discovery of two T dwarf binaries, 2MASS 1225-2739AB and 2MASS 1534-2952AB, identified in a sample of ten T dwarfs imaged with the Hubble Space Telescope Wide Field Planetary Camera 2. The separations of the two…

Brown dwarfs can serve as both clocks and chemical tracers of the evolutionary history of the Milky Way due to their continuous cooling and high sensitivity of spectra to composition. We focus on brown dwarfs in globular clusters that host…

Brown dwarfs form the key, yet poorly understood, link between stellar and planetary astrophysics. These objects offer unique tests of Galactic structure, but observational limitations have inhibited their large-scale analysis to date.…

We present results from high-resolution hydrodynamical simulations which explore the effects of small scale clustering in star-forming regions. A large ensemble of small-N clusters with 5 stellar seeds have been modelled and the resulting…

Two blue-straggler sequences discovered in globular cluster M30 provide a strong constraint on the formation mechanisms of blue stragglers. We study the formation of the blue-straggler binaries through binary evolution, and find that binary…

In dense stellar systems, frequent dynamical interactions between binaries lead to the formation of multiple systems. In this contribution we discuss the dynamical formation of hierarchically stable triples: the formation rate, main…

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…

This paper is the fourth one of a series whose chief objective is studying the influence of different mass spectra on the dynamical evolution of open star clusters. Results from several N-body calculations with primordial binaries and mass…

In Galactic open clusters, there is an apparent paucity of white dwarfs compared to the number expected assuming a reasonable initial mass function and that main-sequence stars with initial mass <= 8 M_sun become white dwarfs. We suggest…

Binaries are very common in galaxies, and more than half of Galactic hot subdwarf stars, which are thought as a possible origin of UV-upturn of old stellar populations, are found in binaries. Previous works showed that binary evolution can…

We report the results of deep infrared observations of brown dwarf candidates in the Trapezium cluster in Orion. Analysis of the JHK color-color diagram indicates that a large fraction (approx 65% +/- 15%) of the observed sources exhibit…

We study the evolution of binary stars in globular clusters using a new Monte Carlo approach combining a population synthesis code (StarTrack), and a simple treatment of dynamical interactions in the dense cluster core using a new tool for…