中文
相关论文

相关论文: The Role of Tiny Grains on the Accretion Process i…

200 篇论文

Weakly ionized protoplanetary disks (PPDs) are subject to non-ideal-magnetohydrodynamic (MHD) effects including Ohmic resistivity, the Hall effect and ambipolar diffusion (AD), and the resulting magnetic diffusivities ($\eta_O, \eta_H$ and…

地球与行星天体物理 · 物理学 2016-03-16 Rui Xu , Xue-Ning Bai

The gas dynamics in protoplanetary disks (PPDs) is strongly affected by non-ideal MHD effects. Using a complex chemical reaction network with standard prescriptions for X-ray and cosmic-ray ionizations, as well as the most up-to-date…

地球与行星天体物理 · 物理学 2015-05-28 Xue-Ning Bai

Substructures in PPDs, whose ubiquity was unveiled by recent ALMA observations, are widely discussed regarding their possible origins. We carry out global full magnetohydrodynamic (MHD) simulations in axisymmetry, coupled with…

地球与行星天体物理 · 物理学 2021-06-09 Xiao Hu , Lile Wang , Satoshi Okuzumi , Zhaohuan Zhu

We investigate the linear growth and vertical structure of the MRI in protoplanetary discs when dust grains are well mixed with the gas over the entire disc thickness. All the grains have the same radius (a = 0.1, 1 or 3 micron) and…

天体物理学 · 物理学 2009-11-13 Raquel Salmeron , Mark Wardle

Magnetic fields likely play a key role in the dynamics and evolution of protoplanetary discs. They have the potential to efficiently transport angular momentum by MHD turbulence or via the magnetocentrifugal acceleration of outflows from…

天体物理学 · 物理学 2009-06-23 Mark Wardle

Magnetic fields ($\textbf{B}$) are an important factor that controls the star formation process. The leading method to observe $\textbf{B}$ is using polarized thermal emission from dust grains aligned with $\textbf{B}$. However, in dense…

星系天体物理 · 物理学 2023-06-16 Nguyen Chau Giang , Thiem Hoang , Jeong-Gyu Kim , Le Ngoc Tram

We consider the inner $\sim$ AU of a protoplanetary disk (PPD), at a stage where angular momentum transport is driven by the mixing of a radial magnetic field into the disk from a T-Tauri wind. Because the radial profile of the imposed…

地球与行星天体物理 · 物理学 2015-12-23 Matthew Russo , Christopher Thompson

We explore the physical origins of the observed deficit of polycyclic aromatic hydrocarbons (PAHs) at sub-solar metallicity using JWST/NIRCam imaging of the nearby galaxy M101, covering regions from solar metallicity (Z$_{\odot}$) down to…

We perform local, vertically stratified shearing-box MHD simulations of protoplanetary disks (PPDs) at a fiducial radius of 1 AU that take into account the effects of both Ohmic resistivity and ambipolar diffusion (AD). The magnetic…

地球与行星天体物理 · 物理学 2015-06-12 Xue-Ning Bai , James M. Stone

Dust polarization induced by aligned grains is widely used to study magnetic fields in various environments, including star-forming regions. However, the question of to what optical depth grain alignment still exists in a dense molecular…

星系天体物理 · 物理学 2021-03-03 Thiem Hoang , Le Ngoc Tram , Hyeseung Lee , Pham Ngoc Diep , Nguyen Bich Ngoc

The structure of magnetic fields within protostellar disks may be studied via polarimetry provided that grains are aligned in respect to magnetic field within the disks. We explore alignment of dust grains by radiative torque in T Tauri…

天体物理学 · 物理学 2009-11-11 Jungyeon Cho , A. Lazarian

The size of dust grains, $a$, is key to the physical and chemical processes in circumstellar disks, but observational constraints of grain size remain challenging. (Sub)millimeter continuum observations often show a percent-level…

We use deep Spitzer mid-infrared spectroscopic maps of radial strips across three nearby galaxies with well-studied metallicity gradients (M101, NGC 628, and NGC 2403) to explore the physical origins of the observed deficit of polycyclic…

We consider the acceleration of very small dust grains including Polycyclic Aromatic Hydrocarbons (PAHs) arising from the electrostatic interactions of dust grains that have charge fluctuations in time due to charging events. We simulate…

星系天体物理 · 物理学 2015-06-03 Thiem Hoang , A. Lazarian

Recent work identified a growth barrier for dust coagulation that originates in the electric repulsion between colliding particles. Depending on its charge state, dust material may have the potential to control key processes towards planet…

地球与行星天体物理 · 物理学 2015-06-03 Martin Ilgner

Thermal dust polarization is a powerful tool to probe magnetic fields ($\textbf{B}$) and grain properties. However, a systematic study of the dependence of dust polarization on grain properties in protostellar environments is not yet…

星系天体物理 · 物理学 2024-03-14 Nguyen Chau Giang , Thiem Hoang

Requirements for magnetic coupling and accretion in the active layer of a protostellar disk are re-examined, and some implications for thermal emission from the layer are discussed. The ionization and electrical conductivity are calculated…

太阳与恒星天体物理 · 物理学 2009-08-05 Xue-Ning Bai , Jeremy Goodman

Turbulent coagulation in protoplanetary disks is known to operate on timescale far shorter than the lifetime of the disk. In the absence of mechanisms that replenish the small dust grain population, protoplanetary disks would rapidly lose…

天体物理学 · 物理学 2009-11-13 C. Dominik , C. P. Dullemond

Planetesimal formation via the streaming and gravitational instabilities of dust in protoplanetary disks requires a local enhancement of the dust-to-gas mass ratio. Radial drift of large grains toward pressure bumps in gas disks is a…

地球与行星天体物理 · 物理学 2024-11-21 Satoshi Okuzumi

Radial substructures have now been observed in a wide range of protoplanetary discs (PPDs), from young to old systems, however their formation is still an area of vigorous debate. Recent magnetohydrodynamic (MHD) simulations have shown that…

太阳与恒星天体物理 · 物理学 2023-08-25 C. A. Nolan , B. Zhao , P. Caselli , Z. Y. Li
‹ 上一页 1 2 3 10 下一页 ›