Related papers: Brown Dwarf Formation: Theory
Binary stars produce an array of dramatic astrophysical phenomena. They allow us to probe stellar structure, nuclear physics, and gravitational wave physics. They also produce the powerful supernovae that allow us to measure the scale of…
Clouds seem like an every-day experience. But -- do we know how clouds form on brown dwarfs and extra-solar planets? How do they look like? Can we see them? What are they composed of? Cloud formation is an old-fashioned but still…
We suggest that planets, brown dwarfs, and even low mass stars can be formed by fragmentation of protoplanetary disks around very massive stars M>~100 solar masses. We discuss how fragmentation conditions make the formation of very massive…
We argue that gravitational instability of typical protostellar disks is not a viable mechanism for the fragmentation into multiple systems -- binary stars, brown dwarf companions, or gas giant planets -- except at periods above roughly…
In this short review, we summarize our present understanding (and non-understanding) of exoplanet formation, structure and evolution, in the light of the most recent discoveries. Recent observations of transiting massive brown dwarfs seem…
There are a few different mechanisms that can cause white dwarf stars to vary in brightness, providing opportunities to probe the physics, structures, and formation of these compact stellar remnants. The observational characteristics of the…
Optical and HI imaging of both dwarf irregular (dI) and Blue Compact Dwarf (BCD) galaxies reveal important clues on how dwarf galaxies evolve and their star formation is regulated. Both usually show evidence for stellar and gaseous disks.…
Optical and HI imaging of gas rich dwarfs, both dwarf irregulars (dI) and blue compact dwarfs (BCD), reveals important clues on how dwarf galaxies evolve and their star formation is regulated. Both types usually show evidence for stellar…
Masses and radii of transiting brown dwarfs can be measured directly in contrast to isolated field brown dwarfs, whose mass and radius inferences are model dependent. Therefore, transiting brown dwarfs are a testbed for the interior and…
Properties of nearby dwarf galaxies are briefly discussed. Dwarf galaxies vary widely in their star formation histories, the ages of their subpopulations, and in their enrichment history. Furthermore, many dwarf galaxies show evidence for…
We present a calculation of protostellar disk formation and evolution in which gaseous clumps (essentially, the first Larson cores formed via disk fragmentation) are ejected from the disk during the early stage of evolution. This is a…
Ground-based and spacecraft telescopic observations, combined with an intensive modeling effort, have greatly enhanced our understanding of hot giant planets and brown dwarfs over the past ten years. Although these objects are all fluid,…
The existence of a deficit of brown dwarfs (BDs) in close orbit around main-sequence stars is one of the most intriguing questions in stellar physics. This so-called BD desert may result from the transition between two different dominant…
Electron-degenerate, pressure-ionized hydrogen (usually referred to as metallic hydrogen) is the principal constituent of brown dwarfs, the long-sought objects which lie in the mass range between the lowest-mass stars (about eighty times…
A local property of standard cosmology - growth of primordial perturbations - implies at least six different formation mechanisms of dwarf galaxies. A global property - the topology of the Universe - may enable direct observational study of…
Dwarf spheroidal galaxies are the most dark matter dominated systems in the nearby Universe and their origin is one of the outstanding puzzles of how galaxies form. Dwarf spheroidals are poor in gas and stars, making them unusually faint,…
Brown dwarfs and very low mass stars are a significant fraction of stars in our galaxy, and they are interesting laboratories to investigate planet formation in extreme conditions of low temperature and densities. In addition, the dust…
(abridged) Sub-stellar mass objects have fundamentally different binary properties than stars implying that they cannot have the same formation history. They are rather unfinished stars having either been ejected by their siblings from…
We investigate the stellar populations of a sample of Tidal Dwarf Galaxies, combining observations and evolutionary synthesis models to try and reveal their formation mechanism. On optical images we select a first sample of TDGs for which…
We present opacity sampling model atmospheres, synthetic spectra and colors for brown dwarfs and very low mass stars in two limiting case of dust grain formation: 1) inefficient gravitational settling i.e. the dust is distributed according…