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相关论文: Alignment and rotational disruption of dust

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Polarimetry is one of the most informative techniques of studying magnetic fields in molecular clouds. How reliable the interpretation of the polarization maps in terms of magnetic fields is the issue that the grain alignment theory…

天体物理学 · 物理学 2016-08-30 A. Lazarian , J. Cho

Dust grains moving at hypersonic velocities of $v_{d}\gtrsim 100\rm km~s^{-1}$ through an ambient gas are known to be destroyed by nonthermal sputtering. Yet, previous studies of nonthermal sputtering disregarded the fact that dust grains…

星系天体物理 · 物理学 2020-07-01 Thiem Hoang , Hyeseung Lee

We study the alignment of grains subject to both radiative torques and pinwheel torques while accounting for thermal flipping of grains. By pinwheel torques we refer to all systematic torques that are fixed in grain body axes, including the…

天体物理学 · 物理学 2009-06-23 T. Hoang , A. Lazarian

Several mechanisms have been proposed to explain the alignment of grains with the interstellar magnetic field, including paramagnetic dissipation, radiative torques, and supersonic gas-grain streaming. These must compete with disaligning…

天体物理学 · 物理学 2008-11-26 Joseph C. Weingartner

While the problem of grain alignment was posed more than 60 years ago the quantitative model of grain alignment that can account for the observed polarization arising from aligned grains has been formulated only recently. The quantitative…

星系天体物理 · 物理学 2009-03-09 A. Lazarian

Massive stars, supernovae, and kilonovae are among the most luminous radiation sources in the universe. Observations usually show near- to mid-infrared (NIR--MIR, $\lambda\sim 1-5~\mu$m) emission excess from H\,{\sc ii} regions around young…

星系天体物理 · 物理学 2019-05-09 Thiem Hoang , Le Ngoc Tram , Hyeseung Lee , Sang-Hyeon Ahn

It is shown, that mechanical alignment can be efficient for suprathermally rotating grains, provided that they drift with supersonic velocities. Such a drift should be widely spread due to both Alfv\'{e}nic waves and ambipolar diffusion.…

天体物理学 · 物理学 2015-06-24 A. Lazarian

The polarization of starlight and thermal dust emission, resulting from non-spherical grains aligned with the interstellar magnetic field (B-field), act as a powerful tool to trace the B-field morphologies and strengths in molecular clouds…

星系天体物理 · 物理学 2026-05-26 Saikhom Pravash

Dust polarization induced by aligned non-spherical grains acts as an important tool to trace the magnetic field (B-field) morphologies and strengths in molecular clouds and constrain grain properties and their alignment mechanisms. The…

星系天体物理 · 物理学 2026-03-03 Saikhom Pravash , Thiem Hoang , Archana Soam , Qi-Lao Gu , Tie Liu , Pham Ngoc Diep , Le Ngoc Tram , Nguyen Bich Ngoc

We study the effect of rotation during the collision between dust aggregates, in order to address a mismatch between previous model calculations of Brownian motion driven aggregation and experiments. We show that rotation during the…

天体物理学 · 物理学 2009-11-11 D. Paszun , C. Dominik

It is shown that mechanical alignment of grains can be efficient for grains rotating suprathermally, i.e. with kinetic energy substantially exceeding $k$ (the Boltzmann constant) over any temperature in the system. The paper studies…

天体物理学 · 物理学 2009-10-28 A. Lazarian

Grain alignment theory suggests that grains should be aligned in circumstellar regions and the observational data available supports this conclusion. We discuss the alignment of grains via (1) magnetic relaxation, (2) mechanical processes,…

天体物理学 · 物理学 2007-05-23 Lazarian A

In protoplanetary discs, the coagulation of dust grains into large aggregates still remains poorly understood. Grain porosity appears to be a promising solution to allow the grains to survive and form planetesimals. Furthermore, dust…

地球与行星天体物理 · 物理学 2023-01-06 Stéphane Michoulier , Jean-François Gonzalez

Located in the Large Magellanic cloud and mostly irradiated by a massive-star cluster R$\,$136, 30 Doradus is an ideal target to test the leading theory of the grain alignment and rotational disruption by RAdiative Torques (RATs). Here, we…

Context. Planck observations demonstrated that the grain alignment efficiency is almost constant in the diffuse ISM. Aims. We test if the Radiative Torque (RAT) theory is compatible with observational constraints on grain alignment.…

天体物理仪器与方法 · 物理学 2020-08-26 Stefan Reissl , Vincent Guillet , Robert Brauer , François Levrier , François Boulanger , Ralf S. Klessen

Atacama Large Millimeter/Submillimeter Array (ALMA) has revolutionized the field of dust polarization in protoplanetary disks across multiple wavelengths. Previous observations and empirical modeling suggested multiple mechanisms of dust…

太阳与恒星天体物理 · 物理学 2024-07-30 Nguyen Tat Thang , Pham Ngoc Diep , Thiem Hoang , Le Ngoc Tram , Nguyen Bich Ngoc , Nguyen Thi Phuong , Bao Truong

In a previous work, Hoang and Tram discovered a new mechanism for destruction of nanoparticles due to suprathermal rotation of grains in stationary C-shocks, which is termed rotational disruption. In this paper, we extend our previous study…

星系天体物理 · 物理学 2020-01-08 Le Ngoc Tram , Thiem Hoang

Motivated by a recent study by Lazarian and Draine, which showed that a high degree of grain alignment of the paramagnetic dust is achievable if the rates of internal relaxation are controlled by the Barnett relaxation process, we undertake…

天体物理学 · 物理学 2009-10-31 A. Lazarian , M. Efroimsky

We study the internal and external alignment of carbonaceous grains, including graphite and hydrogenated amorphous carbon (HAC), in the interstellar medium (ISM) within the RAdiative Torque (RAT) paradigm. For internal alignment (IA), we…

星系天体物理 · 物理学 2023-01-20 Thiem Hoang , Vo Hong Minh Phan , Le Ngoc Tram

In the previous papers in this series, we found that radiative torques can play a major role in the alignment of grains with the interstellar magnetic field. Since the radiative torques can drive the grains to suprathermal rotational…

天体物理学 · 物理学 2009-11-07 Joseph C. Weingartner , B. T. Draine