Related papers: On the stability of non-isothermal Bonnor-Ebert sp…
Aims. We investigate the stability of non-isothermal Bonnor-Ebert spheres with a model that includes a self-consistent calculation of the gas temperature. This way we can discard the assumption of equality between the dust and gas…
Aims. We investigate the effect of chemistry on the stability of starless cores against gravitational collapse. Methods. We combine chemical and radiative transfer simulations in the context of a modified Bonnor-Ebert sphere to model the…
We have considered the thermal equilibrium in pre-protostellar cores in the approximation where the dust temperature is independent of interactions with the gas and where the gas is heated both by collisions with dust grains and ionization…
In order to understand the collapse dynamics of observed low-mass starless cores, we revise the conventional stability condition of hydrostatic Bonnor-Ebert spheres to take internal motions into account. Because observed starless cores…
The gravitational collapse of a spherical cloud core is investigated by numerical calculations. The initial conditions of the core lie close to the critical Bonnor-Ebert sphere with a central density of \sim 10^4 cm^{-3} in one model…
Radial density profiles for the sample of dense cores associated with high-mass star-forming regions from southern hemisphere have been derived using the data of observations in continuum at 250 GHz. Radial density profiles for the inner…
We have modeled the emission from dust in pre-protostellar cores, including a self-consistent calculation of the temperature distribution for each input density distribution. Model density distributions include Bonnor-Ebert spheres and…
We study quasi-static atmospheres of accreting protoplanetary cores for different opacity behaviors and realistic planetesimal accretion rates in various parts of protoplanetary nebula. Atmospheres segregate into those having outer…
We used near-infrared 2MASS data to construct visual extinction maps of a sample of Southern Bok globules utilizing the NICE method. We derived radial extinction profiles of dense cores identified in the globules and analyzed their…
We investigate the Hierarchical Gravitational Fragmentation scenario through numerical simulations of the prestellar stages of the collapse of a marginally gravitationally unstable isothermal sphere immersed in a strongly gravitationally…
We have investigated the physical and chemical status of the pre-protostellar core B68. A previous extinction study suggested that the density profile of B68 is remarkably consistent with a Bonnor-Ebert sphere with 2.1 $M_{\odot}$ at 16 K.…
(Abridged) We present numerical hydrodynamical simulations of the formation, evolution and gravitational collapse of isothermal molecular cloud cores. A compressive wave is set up in a constant sub-Jeans density distribution of radius r = 1…
The interest in the structure of ice-rich planetary bodies, in particular the differentiation between ice and rock, has grown due to the discovery of Kuiper belt objects and exoplanets. We thus carry out a parameter study for a range of…
We have computed the dust temperature distribution to be expected in a pre-protostellar core in the phase prior to the onset of gravitational instability. We have done this in the approximation that the heating of the dust grains is solely…
Observations have been carried out with SCUBA at the JCMT of 52 molecular cloud cores that do not contain any sign of protostellar activity. These are all therefore candidate prestellar cores, which are believed to represent the stage of…
Context. Protoplanetary discs are formed due to the fragmentation and collapse of giant molecular cloud cores. The physical properties and structure of a formed disc are of great importance when studying the onset of planet formation…
On the basis of near-infrared imaging observations, we derived visual extinction (Av) distribution toward ten Bok globules through measurements of both the color excess (E_{H-K}) and the stellar density at J, H, and Ks (star count). Radial…
Pre-stellar cores within molecular clouds provide the very initial conditions in which stars are formed. We use the IRAM 30m telescope and the PdBI to study the chemical and physical properties of the starless core FeSt 1-457 (Core 109), in…
In a previous paper we demonstrated that non-radial hydrodynamic oscillations of a thermally-supported (Bonnor-Ebert) sphere embedded in a low-density, high-temperature medium persist for many periods. The predicted column density…
Following an approach initially outlined by McKee & Holliman, we investigate the structure and stability of dense, starless molecular cloud cores. We model those as spherical clouds in hydrostatic equilibrium and supported against gravity…