Related papers: The coolest 'stars' are free-floating planets
We describe a model for the long term evolution of a circumplanetary disk that is fed mass from a circumstellar disk and contains regions of low turbulence (dead zones). We show that such disks can be subject to accretion driven outbursts,…
The evolution of protoplanetary discs embedded in stellar clusters depends on the age and the stellar density in which they are embedded. Stellar clusters of young age and high stellar surface density destroy protoplanetary discs by…
Inside-Out Planet Formation (IOPF) proposes that the abundant systems of close-in Super-Earths and Mini-Neptunes form in situ at the pressure maximum associated with the Dead Zone Inner Boundary (DZIB). We present a model of physical and…
Our current understanding of the physical processes of star formation is reviewed, with emphasis on processes occurring in molecular clouds like those observed nearby. The dense cores of these clouds are predicted to undergo gravitational…
Transitional disks are protoplanetary disk around young stars that display inner holes in the dust distribution within a few AU, which is accompanied nevertheless by some gas accretion onto the central star. These cavities could possibly be…
Classical T Tauri stars (CTTS) are surrounded by actively accreting disks. According to current models material falls along the magnetic field lines from the disk with more or less free-fall velocity onto the star, where the plasma heats up…
Giant planets grow and acquire their gas envelope during the disk phase. At the time of the discovery of giant planets in their host disk, it is important to understand the interplay between the host disk and the envelope and…
The extreme astrophysical processes and conditions that characterize the early Universe are expected to result in young galaxies that are dynamically different from those observed today. This is because the strong effects associated with…
(abbreviated) We report detection with the Spitzer Space Telescope of cool dust surrounding solar type stars. The observations were performed as part of the Legacy Science Program, ``Formation and Evolution of Planetary Systems'' (FEPS).…
While it is widely accepted that planets are formed in protoplanetary disks, there is still much debate on when this process happens. In a few cases protoplanets have been directly imaged, but for the vast majority of systems, disk gaps and…
The core accretion hypothesis posits that planets with significant gaseous envelopes accreted them from their protoplanetary discs after the formation of rocky/icy cores. Observations indicate that such exoplanets exist at a broad range of…
[abridged] Protoplanetary disks with AU-scale inner clearings, often referred to as transitional disks, provide a unique sample for understanding disk dissipation mechanisms and possible connections to planet formation. Observations of…
Gas-giant planets, like Jupiter and Saturn, acquire massive gaseous envelopes during the approximately 3 Myr-long lifetimes of protoplanetary discs. In the core accretion scenario, the formation of a solid core of around 10 Earth masses…
Spitzer observations of the young star CoKuTau/4 reveal a disk with a 10 AU hole that is most likely caused by a newly formed planet. Assuming that the planet opened a gap in the viscous disk, we estimate that the planet mass is greater…
Central cluster galaxies in cooling flows show the signatures of gaseous accretion and ongoing star formation at rates ranging between 1-100 solar masses per year. Their blue morphologies usually reflect the low net angular momentum content…
Doppler surveys have shown that more massive stars have significantly higher frequencies of giant planets inside $\sim$ 3 AU than lower mass stars, consistent with giant planet formation by core accretion. Direct imaging searches have begun…
There are now two dominant models of how stars form: gravitational collapse theory holds that star-forming molecular clumps, typically hundreds to thousands of solar masses in mass, fragment into gaseous cores that subsequently collapse to…
The sample of known exoplanets is strongly biased to masses larger than the ones of the giant gaseous planets of the solar system. Recently, the discovery of two extrasolar planets of considerably lower masses around the nearby stars GJ 436…
We find that free-floating planets can remain bound to a star cluster for much longer than was previously assumed: of the order of the cluster half-mass relaxation timescale as opposed to the crossing-time. This result is based on N-body…
In previous works, we have shown that stars in the Orion and the Lagoon Nebula Clusters, and simulations of collapsing clouds, exhibit constant velocity dispersion as a function of mass, a result described by Lynden-Bell 50 years ago as an…