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Star formation begins with the gravitational collapse of a dense core inside a molecular cloud. As the collapse progresses, the centre of the core begins to heat up as it becomes optically thick. The temperature and density in the centre…

Solar and Stellar Astrophysics · Physics 2015-06-16 N. Vaytet , G. Chabrier , E. Audit , B. Commercon , J. Masson , J. Ferguson , F. Delahaye

Unbiased analysis shows that IRAS data reliably differentiate between the early and late stages of stellar evolution because objects at these stages clearly segregate in infrared color-color diagrams. Structure in these diagrams is…

Astrophysics · Physics 2009-10-31 Zeljko Ivezic , Moshe Elitzur

We investigated the effect of time-dependent ice growth on dust grains on the opacity and hence on the dust temperature in a collapsing molecular cloud core, with the aim of quantifying the effect of the dust temperature variations on ice…

Astrophysics of Galaxies · Physics 2024-10-16 O. Sipilä , P. Caselli , M. Juvela

Recently, crust cooling times have been measured for neutron stars after extended outbursts. These observations are very sensitive to the thermal conductivity $\kappa$ of the crust and strongly suggest that $\kappa$ is large. We perform…

Astrophysics · Physics 2009-11-13 C. J. Horowitz , O. L. Caballero , D. K. Berry

(Abridged) Aims & Methods. A two-dimensional, semi-analytical model is presented that follows, for the first time, the chemical evolution from a collapsing molecular cloud (a pre-stellar core) to a protostar and circumstellar disk. The…

Solar and Stellar Astrophysics · Physics 2009-11-13 R. Visser , E. F. van Dishoeck , S. D. Doty , C. P. Dullemond

We use the COMPLETE Survey's observations of the Perseus star-forming region to assess and intercompare three methods for measuring column density in molecular clouds: extinction mapping (NIR); thermal emission mapping (FIR); and mapping…

Astrophysics · Physics 2011-02-11 Alyssa A. Goodman , Jaime E. Pineda , Scott L. Schnee

In this paper we present the results of a high resolution (5") CARMA and SZA survey of the 3mm continuum emission from 11 of the brightest (at 1.1mm) starless cores in the Perseus molecular cloud. We detect 2 of the 11 cores, both of which…

Astrophysics of Galaxies · Physics 2015-05-19 Scott Schnee , Melissa Enoch , Doug Johnstone , Thomas Culverhouse , Erik Leitch , Daniel P. Marrone , Anneila Sargent

[Abridged] We consider two clusters (A496 and Coma) that are representative of the two classes of cool-core and non-cool-core clusters. We first refer to a two-component dynamical model that ignores the contribution from the galaxy density…

Astrophysics · Physics 2010-11-11 C. De Boni , G. Bertin

We present numerical investigations into the formation of massive stars from centrally condensed turbulent cores. The results of five hydrodynamical simulations are described, following the collapse of the core, fragmentation and the…

Astrophysics · Physics 2009-11-10 Clare L. Dobbs , Ian A. Bonnell , Paul C. Clark

(Abridged) We present a series of decaying turbulence simulations that represent a cluster-forming clump within a molecular cloud, investigating the role of magnetic fields on the formation of potential star-forming cores. We present an…

Astrophysics · Physics 2007-11-07 David A. Tilley , Ralph E. Pudritz

The process of a non-equilibrium chemical composition formation in the crust of a new born neutron star is considered, during cooling due to neutrino energy losses. A model is constructed for explaining accumulation of a large quantity of…

High Energy Astrophysical Phenomena · Physics 2022-03-31 A. Yu. Ignatovskiy , G. S. Bisnovatyi-Kogan

The mass of prestellar cores is an essential ingredient to understand the onset of star formation in the core. The low level of emission from cold dust may keep parts of it hidden from observation. We aim to determine the fraction of core…

Astrophysics of Galaxies · Physics 2016-09-21 Juergen Steinacker , Hendrik Linz , Henrik Beuther , Thomas Henning , Aurore Bacmann

Superconductors like other solids cannot relax instantaneously from excited states to thermodynamic equilibrium. In this paper, relaxation from thermal excitations is investigated, like after absorption of radiation or, under conductor…

Superconductivity · Physics 2021-11-19 Harald Reiss

We investigate the physical properties of dense cores formed in turbulent, magnetized, parsec-scale clumps of molecular clouds, using three-dimensional numerical simulations that include protostellar outflow feedback. The dense cores are…

Solar and Stellar Astrophysics · Physics 2015-05-28 Fumitaka Nakamura , Zhi-Yun Li

Pre-stellar cores represent the initial conditions in the process of star and planet formation. Their low temperatures ($<$10 K) allow the formation of thick icy dust mantles, which will be partially preserved in the future protoplanetary…

We study conditions under which carbon clusters of different sizes form and stabilize. {We describe an approach to equilibrium by simulating tenuous carbon gas dynamics to long times.} First, we use reactive molecular dynamics simulations…

Astrophysics of Galaxies · Physics 2015-06-18 N. Patra , P. Kral , H. R. Sadeghpour

We have recalculated interior structure of very massive stars of uniform chemical composition with the OPAL opacity. Very massive stars are found to develop a core-halo structure with a extended radiative-envelope. With the core-halo…

Astrophysics · Physics 2015-06-24 Mie Ishii , Mariko Kato , Munetaka Ueno

Mass segregation is seen in many star clusters, but whether massive stars form in the center of a cluster or migrate there dynamically is still debated. N-body simulations have shown that early dynamical mass segregation is possible when…

In this paper, we review some of the properties of dense molecular cloud cores. The results presented here rely on three-dimensional numerical simulations of isothermal, magnetized, turbulent, and self-gravitating molecular clouds (MCs) in…

Astrophysics · Physics 2008-08-29 Sami Dib , Roberto Galvan-Madrid , Jongsoo Kim , Enrique Vazquez-Semadeni

With central densities as high as 5-10 times the nuclear saturation density, neutron stars exhibit extreme conditions that cannot be observed elsewhere. They are ideal astrophysical laboratories for probing the composition and properties of…

Solar and Stellar Astrophysics · Physics 2019-09-04 Sophia Han