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The formation of a solar system is believed to have followed a multi-stage process around a protostar. Whipple first noted that planetesimal growth by particle agglomeration is strongly influenced by gas drag; there is a "bottleneck" at the…

地球与行星天体物理 · 物理学 2015-03-13 J. S. Wettlaufer

Supermassive stars (SMSs) forming via very rapid mass accretion (Mdot >~ 0.1 Msun/yr) could be precursors of supermassive black holes observed beyond redshift of about 6. Extending our previous work, we here study the evolution of…

太阳与恒星天体物理 · 物理学 2015-06-16 Takashi Hosokawa , Harold W. Yorke , Kohei Inayoshi , Kazuyuki Omukai , Naoki Yoshida

Two significant progresses have been made in the past years on our understanding of hot accretion flows. One is that only a small fraction of accretion flow available at the outer boundary can finally falls onto the black hole while most of…

高能天体物理现象 · 物理学 2015-06-05 Fu-Guo Xie , Feng Yuan

We investigate the first emergence of the so-called cold accretion, the accretion flows deeply penetrating a halo, in the early universe with cosmological N-body/SPH simulations. We study the structure of the accretion flow and its…

星系天体物理 · 物理学 2023-05-24 Masaki Kiyuna , Takashi Hosokawa , Sunmyon Chon

We present some important conclusions from recent calculations pertaining to the collapse of rotating molecular cloud cores with axial symmetry, corresponding to evolution of young stellar objects through classes 0 and begin of class I.…

太阳与恒星天体物理 · 物理学 2015-05-13 W. M. Tscharnuter , J. Schönke , H. -P. Gail , E. Lüttjohann

Stars may be assembled in large growth spurts, however the evidence for this hypothesis is circumstantial. Directly studying the accretion at the earliest phases of stellar growth is challenging because young stars are deeply embedded in…

太阳与恒星天体物理 · 物理学 2015-06-12 Doug Johnstone , Benjamin Hendricks , Gregory J. Herczeg , Simon Bruderer

We study the structure and evolution of the very early protostellar disk (``protodisk'') just after protostar formation, where disk self-gravity dominates and the stellar contribution is dynamically minor. The disk redistributes angular…

太阳与恒星天体物理 · 物理学 2026-02-05 Majd Noel , Rahul Khanna , Shahram Abbassi , Sami Dib , Shantanu Basu

We present a method of determining lower limits on the masses of pre-main-sequence (PMS) stars and so constraining the PMS evolutionary tracks. This method uses the red-shifted absorption feature observed in some emission-line profiles of T…

We calculate the evolution of cloud cores embedded in different envelopes to investigate environmental effects on the mass accretion rate onto protostars. As the initial state, we neglect the magnetic field and cloud rotation, and adopt…

太阳与恒星天体物理 · 物理学 2023-01-11 Shingo Nozaki , Masahiro N. Machida

Supermassive primordial stars forming in atomically-cooled halos at $z \sim15-20$ are currently thought to be the progenitors of the earliest quasars in the Universe. In this picture, the star evolves under accretion rates of $0.1 - 1$…

太阳与恒星天体物理 · 物理学 2017-12-27 Lionel Haemmerlé , Tyrone E. Woods , Ralf S. Klessen , Alexander Heger , Daniel J. Whalen

We construct a model for cosmic ray acceleration from protostellar accretion shocks and calculate the resulting cosmic ray ionization rate within star-forming molecular clouds. We couple a protostar cluster model with an analytic accretion…

星系天体物理 · 物理学 2018-07-25 Brandt A. L. Gaches , Stella S. R. Offner

Knowledge of protostellar evolution has been revolutionized with the advent of surveys at near-infrared to submillimeter wavelengths. This has enabled the bolometric luminosities and bolometric temperatures (traditional protostellar…

Newly formed stars are often observed to possess circumstellar disks, from which mass continues to be accreted onto the star and fed into outflowing jets, and which eventually may evolve into dusty debris disks and planetary systems. Recent…

天体物理学 · 物理学 2007-05-23 A. Konigl

We investigate the formation of the first stars at the end of the cosmic dark ages with a suite of three-dimensional, moving mesh simulations that directly resolve the collapse of the gas beyond the formation of the first protostar at the…

宇宙学与河外天体物理 · 物理学 2015-06-04 Thomas H. Greif , Volker Bromm , Paul C. Clark , Simon C. O. Glover , Rowan J. Smith , Ralf S. Klessen , Naoki Yoshida , Volker Springel

We investigate the upper stellar mass limit set by radiative feedback by the forming star with various accretion rates and metallicities. To this end, we numerically solve the structures of both a protostar and its surrounding accretion…

太阳与恒星天体物理 · 物理学 2017-12-06 Hajime Fukushima , Kazuyuki Omukai , Takashi Hosokawa

In the poster presented in Cool Star 15, we analyzed the effect of disk accretion on the evolution of very low mass pre-main sequence stars and young brown dwarfs and the resulting uncertainties on the determination of masses and ages. We…

天体物理学 · 物理学 2009-11-13 Jose Gallardo , Isabelle Baraffe , Gilles Chabrier

The formation of SMSs is a potential pathway to seed SMBHs in the early universe. A critical issue for forming SMSs is stellar UV feedback, which may limit the stellar mass growth via accretion. In this paper we study the evolution of an…

太阳与恒星天体物理 · 物理学 2016-03-23 Yuya Sakurai , Eduard I. Vorobyov , Takashi Hosokawa , Naoki Yoshida , Kazuyuki Omukai , Harold W. Yorke

An observational review is provided of the properties of accretion disks around young stars. It concerns the primordial disks of intermediate- and high-mass young stellar objects in embedded and optically revealed phases. The properties…

星系天体物理 · 物理学 2016-02-24 M. T. Beltran , W. J. de Wit

It is reasonable to assume that the structure of a planet and the interior distribution of its components are determined by its formation history. We thus follow the growth of a planet from a small embryo through its subsequent evolution.…

地球与行星天体物理 · 物理学 2022-08-03 Michael Lozovsky , Dina Prialnik , Morris Podolak

The evolution of protostellar outflow is investigated with resistive magneto-hydrodynamic nested-grid simulations that cover a wide range of spatial scales (\sim 1AU - 1pc). We follow cloud evolution from the pre-stellar core stage until…

太阳与恒星天体物理 · 物理学 2015-06-15 Masahiro N. Machida , Takashi Hosokawa
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