Related papers: The coolest 'stars' are free-floating planets

The origin of a recently discovered close-in Neptune-mass planet around GJ436 poses a challenge to the current theories of planet formation. Based on the sequential accretion hypothesis and the standard theory of gap formation and orbital…

Young stars and planetary systems form in molecular clouds. For classical T Tauri stars (CTTS, F-K type precursors) the accretion disk does not reach down to the central star, but it is truncated near the co-rotation radius. The inner edge…

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…

M dwarf stars, which have masses less than 60 per cent that of the Sun, make up 75 per cent of the population of the stars in the Galaxy [1]. The atmospheres of orbiting Earth-sized planets are observationally accessible via transmission…

The planetary mass-radius diagram is an observational result of central importance to understand planet formation. We present an updated version of our planet formation model based on the core accretion paradigm which allows to calculate…

Circumplanetary disks can be found around forming giant planets, regardless of whether core accretion or gravitational instability built the planet. We carried out state-of-the-art hydrodynamical simulations of the circumplanetary disks for…

During the last three decades, evidence has mounted that star and planet formation is not an isolated process, but is influenced by current and previous generations of stars. Although cool stars form in a range of environments, from…

The formation and evolution of a circumstellar disk in magnetized cloud cores is investigated from prestellar core stage until sim 10^4 yr after protostar formation. In the circumstellar disk, fragmentation first occurs due to gravitational…

We investigate the ab-initio formation of super-massive stars in a pristine atomic cooling halo. The halo is extracted from a larger self-consistent parent simulation. The halo remains metal-free and star formation is suppressed due to a…

We study the evolution of planetesimals in evolved gaseous disks, which orbit a solar-mass star and harbor a Jupiter-mass planet at a_p~5AU. The gas dynamics is modeled with a three-dimensional hydrodynamics code that employes nested-grids…

We examine gas accretion and subsequent star formation in representative galaxies from the McMaster Unbiased Galaxy Simulations (Stinson et al. 2010). Accreted gas is bimodal with a natural temperature division at $10^5$ K, near the peak of…

Observations indicate that massive stars form in regions of very high surface density, ~1 g cm^-2. Clusters containing massive stars and globular clusters have a comparable column density. The total pressure in clouds of such a column…

Direct-imaging surveys have looked for accreting planets through their accretion tracers such as H alpha but have been less fruitful than expected. However, up to now, hydrogen-line emission at accreting planets has been estimated primarily…

Hot Jupiters have been perceived as loners devoid of planetary companions in close orbital proximity. However, recent discoveries based on space-borne precise photometry have revealed that at least some fraction of giant planets coexists…

Formation of planets in the Neptune size range with low-mass, but voluminous, H_2/He gaseous envelopes is modeled by detailed numerical simulations according to the core-nucleated accretion scenario. Formation locations ranging from 0.5 to…

We explore the possibility that, in the vicinity of an OB star, a prestellar core which would otherwise have formed an intermediate or low-mass star may form a free-floating brown dwarf or planetary-mass object, because the outer layers of…

(Abridged) We consider models of gas giant planets forming in protoplanetary disks consisting of solid cores with gaseous envelopes in contact with their critical Hill spheres while accreting gas from the surrounding disk.We suppose the…

Measured disk masses seem to be too low to form the observed population of planetary systems. In this context, we develop a population synthesis code in the pebble accretion scenario, to analyse the disk mass dependence on planet formation…

Hot Jupiters are giant Jupiter-like exoplanets that orbit 100x closer to their host stars than Jupiter does to the Sun. These planets presumably form in the outer part of the primordial disc from which both the central star and surrounding…

To understand giant planet formation, we need to focus on host stars close to $1.7\ \rm M_{\odot}$, where the occurrence rate of these planets is the highest. In this initial study, we carry out pebble-driven core accretion planet formation…