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We present the results of a single-pointing survey of 207 dense cores embedded in Planck Galactic Cold Clumps distributed in five different environments ($\lambda$ Orionis, Orion A, B, Galactic plane, and high latitudes) to identify dense…

In Hot or Warm Dark Matter universes the density fluctuations at early times contain very little power below a characteristic wavelength related inversely to the particle mass. We study how discreteness noise influences the growth of…

Astrophysics · Physics 2007-08-23 Jie Wang , Simon D. M. White

The formation mechanism of Brown Dwarfs (BDs), whether akin to stars or ejected planetary-mass objects, remains debated. We present the first 3D radiation-MHD simulations of magnetized, turbulent, gravitationally unstable low-mass cores…

Solar and Stellar Astrophysics · Physics 2025-09-17 Adnan Ali Ahmad , Benoît Commerçon , Gilles Chabrier , Antonin Borderies

The major aim of this study is to assess the effects of sintering of initially porous material on the thermal evolution of planetesimals, and to constrain the values of basic parameters that determined the structure and evolution of the H…

Earth and Planetary Astrophysics · Physics 2015-05-30 Stephan Henke , Hans-Peter Gail , Mario Trieloff , Winfried H. Schwarz , Thorsten Kleine

We study the formation and long-term evolution of primordial protostellar disks harbored by first stars using numerical hydrodynamics simulations in the thin-disk limit. The initial conditions are specified by pre-stellar cores with…

Astrophysics of Galaxies · Physics 2015-06-15 Eduard I. Vorobyov , Alexander L. DeSouza , Shantanu Basu

Recent observations point to the presence of structured dust grains in the discs surrounding young brown dwarfs, thus implying that the first stages of planet formation take place also in the sub-stellar regime. Here, we investigate the…

Astrophysics · Physics 2009-11-13 Matthew J. Payne , Giuseppe Lodato

We are reporting the observation of the breakdown of electrons degeneracy and emergence of classical statistics in the simplest element: metallic deuterium. We have studied the optical reflectance, shock velocity and temperature of…

Plasma Physics · Physics 2019-03-27 M. Zaghoo , T. R. Boehly , J. R. Rygg , P. M. Celliers , S. X. Hu , G. W. Collins

Direct imaging searches have revealed many very low-mass objects, including a small number of planetary mass objects, as wide-orbit companions to young stars. The formation mechanism of these objects remains uncertain. In this paper we…

Astrophysics of Galaxies · Physics 2015-06-24 Dimitris Stamatellos , Gregory J. Herczeg

Brown dwarfs are essential targets for understanding planetary and sub-stellar atmospheres across a wide range of thermal and chemical conditions. As surveys continue to probe ever deeper, and as observing capabilities continue to improve,…

Earth and Planetary Astrophysics · Physics 2021-11-24 Shih-Yun Tang , Tyler D. Robinson , Mark S. Marley , Natasha E. Batalha , Roxana Lupu , L. Prato

Recent structure models of Jupiter suggest the existence of an extended region in the deep interior with a high heavy element abundance, referred to as a dilute core. This finding has led to increased interest in modelling the formation and…

Earth and Planetary Astrophysics · Physics 2024-12-02 Jesse Polman , Christoph Mordasini

White dwarfs that have accreted planetary materials provide a powerful tool to probe the interiors and formation of exoplanets. In particular, the high Fe/Si ratio of some white dwarf pollutants suggests that they are fragments of bodies…

Earth and Planetary Astrophysics · Physics 2023-10-27 Yuqi Li , Amy Bonsor , Oliver Shorttle

Mass is the fundamental parameter that governs the evolution of stars, brown dwarfs, and gas-giant planets. Thus, direct mass measurements are essential to test the evolutionary and atmospheric models that underpin studies of these objects.…

Solar and Stellar Astrophysics · Physics 2011-03-31 Trent J. Dupuy , Michael C. Liu , Michael J. Ireland

(Abridged) A numerical model of a circumstellar debris disk is developed and applied to observations of the circumstellar dust orbiting beta Pictoris. The model accounts for the rates at which dust is produced by collisions among unseen…

Earth and Planetary Astrophysics · Physics 2015-05-19 Joseph M. Hahn

The primordial abundance of deuterium produced during Big Bang Nucleosynthesis (BBN) depends sensitively on the universal ratio of baryons to photons, an important cosmological parameter probed independently by the Cosmic Microwave…

Astrophysics of Galaxies · Physics 2015-05-13 Gary Steigman

The pre-main-sequence evolution of low-mass stars and brown dwarfs is studied numerically starting from the formation of a protostellar/proto-brown dwarf seed and taking into account the mass accretion onto the central object during the…

Solar and Stellar Astrophysics · Physics 2017-09-20 Eduard Vorobyov , Vardan Elbakyan , Takashi Hosokawa , Yuya Sakurai , Manuel Guedel , Harold Yorke

The prejudice against baryon isocurvature models is primarily because of their inconsistency with early universe light element nucleosynthesis results. We propose that incipient low metallicity (Pop II) star forming regions can be expected…

Astrophysics · Physics 2007-05-23 D. Lohiya , P. Kumar

Theory and simulations suggest that it is possible to form low-mass hydrogen-burning stars, brown dwarfs and planetary-mass objects via disc fragmentation. As disc fragmentation results in the formation of several bodies at comparable…

Solar and Stellar Astrophysics · Physics 2015-06-11 Yun Li , M. B. N. Kouwenhoven , D. Stamatellos , S. P. Goodwin

The purpose of this work is to explore the evolution of helium-core white dwarf stars in a self-consistent way with the predictions of detailed non-gray model atmospheres and element diffusion. To this end, we consider helium-core white…

Astrophysics · Physics 2009-11-06 A. M. Serenelli , L. G. Althaus , R. D. Rohrmann , O. G. Benvenuto

In close binary systems composed of a normal, donor star and an accreting neutron star, the amount of material received by the accreting component is, so far, a real intrigue. In the literature there are available models that link the…

Solar and Stellar Astrophysics · Physics 2015-06-04 M. A. De Vito , O. G. Benvenuto

Some thermonuclear (type I) X-ray bursts at the neutron star surfaces in low-mass X-ray binaries take place during hard persistent states of the systems. Spectral evolution of these bursts is well described by the atmosphere model of a…

High Energy Astrophysical Phenomena · Physics 2018-12-17 V. F. Suleimanov , J. Poutanen , K. Werner