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Using resistive magnetohydrodynamics simulations, the propagation of protostellar jets, the formation of circumstellar discs and the configuration of magnetic fields are investigated from the prestellar cloud phase until $\sim$500 yr after…

Solar and Stellar Astrophysics · Physics 2020-01-08 Masahiro N. Machida , Shingo Hirano , Hideyuki Kitta

We explore how the expulsion of gas from star-cluster forming cloud-cores due to supernova explosions affects the shape of the initial cluster mass function, that is, the mass function of star clusters when effects of gas expulsion are…

Astrophysics · Physics 2009-11-13 G. Parmentier , S. P. Goodwin , P. Kroupa , H. Baumgardt

The protostellar jets driven by the formation of the first stars are studied by using MHD nested grid simulations. Starting from a slowly rotating spherical cloud of 5.1 times 10^4 Msun permeated by a uniform magnetic field, we follow the…

We present radiation hydrodynamic simulations of collapsing protostellar cores with initial masses of 30, 100, and 200 M$_{\odot}$. We follow their gravitational collapse and the formation of a massive protostar and protostellar accretion…

Astrophysics of Galaxies · Physics 2016-05-25 Mikhail Klassen , Ralph Pudritz , Rolf Kuiper , Thomas Peters , Robi Banerjee

We revisit the problem of the formation of dense protostellar cores due to ambipolar diffusion within magnetically supported molecular clouds, and derive an analytical expression for the core formation timescale. The resulting expression is…

Astrophysics · Physics 2009-10-31 Glenn E. Ciolek , Shantanu Basu

We report the results of our three-dimensional radiation hydrodynamics simulation of collapsing unmagnetized molecular cloud cores. We investigate the formation and evolution of the circumstellar disk and the clumps formed by disk…

Solar and Stellar Astrophysics · Physics 2015-06-16 Yusuke Tsukamoto , Masahiro N. Machida , Shuichiro Inutsuka

On average molecular clouds convert only a small fraction epsilon_ff of their mass into stars per free-fall time, but differing star formation theories make contrasting claims for how this low mean efficiency is achieved. To test these…

Astrophysics of Galaxies · Physics 2022-02-09 Zipeng Hu , Mark R. Krumholz , Riwaj Pokhrel , Robert A. Gutermuth

Momentum deposition by radiation pressure from young, massive stars may help to destroy molecular clouds and unbind stellar clusters by driving large-scale outflows. We extend our previous numerical radiation hydrodynamic study of…

Astrophysics of Galaxies · Physics 2017-12-06 Sudhir Raskutti , Eve C. Ostriker , M. Aaron Skinner

We have simulated star formation in prestellar cores, using SPH and initial conditions informed by observations of the cores in Ophiuchus. Because the observations are limited to two spatial dimensions plus radial velocity, we cannot infer…

Solar and Stellar Astrophysics · Physics 2014-03-05 O. Lomax , A. P. Whitworth , D. A. Hubber , D. Stamatellos , S. Walch

We present the results of a numerical simulation in which star formation proceeds from an initially unbound molecular cloud core. The turbulent motions, which dominate the dynamics, dissipate in shocks leaving a quiescent region which…

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

We have carried out sensitive 1.3 mm observations of 20 young brown dwarfs in the Taurus star-forming region, representing the largest sample of young substellar objects targeted in a deep millimeter continuum survey to date. Under standard…

Astrophysics · Physics 2009-11-11 Alexander Scholz , Ray Jayawardhana , Kenneth Wood

We calculate numerically the collapse of slowly rotating, non-magnetic, massive molecular clumps, which conceivably could lead to the formation of massive stars. Because radiative acceleration on dust grains plays a critical role in the…

Astrophysics · Physics 2009-11-07 Harold W. Yorke , Cordula Sonnhalter

We have surveyed 84 Class 0, Class I, and flat-spectrum protostars in mid-infrared [Si II], [Fe II] and [S I] line emission, and 11 of these in far-infrared [O I] emission. We use the results to derive their mass outflow rates. Thereby we…

We investigate the properties of "star forming regions" in a previously published numerical simulation of molecular cloud formation out of compressive motions in the warm neutral atomic interstellar medium, neglecting magnetic fields and…

We model the formation of high-mass stars, specifying the accretion rate in terms of the instantaneous and final mass of the star, the ambient pressure of the star-forming region and the form of polytropic pressure support of the…

Astrophysics · Physics 2007-05-23 Jonathan C. Tan , Christopher F. McKee

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…

Solar and Stellar Astrophysics · Physics 2015-05-27 Masahiro N. Machida , Shu-ichiro Inutsuka , Tomoaki Matsumoto

We show that the dearth of brown dwarfs in short-period orbits around Solar-mass stars - the brown dwarf desert - can be understood as a consequence of inward migration within an evolving protoplanetary disc. Brown dwarf secondaries forming…

Astrophysics · Physics 2009-11-07 Philip J. Armitage , Ian A. Bonnell

We investigate how the external medium surrounding prestellar cores affects the star formation process by conducting three-dimensional resistive magnetohydrodynamic simulations. The initial cores follow critical Bonnor-Ebert profiles and…

Astrophysics of Galaxies · Physics 2025-10-29 Shingo Nozaki , Masahiro N. Machida

A large fraction of brown dwarfs and low-mass stars may form by gravitational fragmentation of relatively massive (a few 0.1 Msun), extended (a few hundred AU) discs around Sun-like stars. We present an ensemble of radiative hydrodynamic…

Astrophysics of Galaxies · Physics 2015-05-20 Dimitris Stamatellos , Anthony Whitworth

We investigate how the removal of interstellar material by stellar feedback limits the efficiency of star formation in molecular clouds and how this determines the shape of the mass function of young star clusters. In particular, we derive…

Solar and Stellar Astrophysics · Physics 2015-05-14 S. Michael Fall , Mark R. Krumholz , Christopher D. Matzner