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Colloquium

Grain alignment, rotational disruption and implications

2022-03-25
  • Speaker : Dr. Le Ngoc Tram (Max-Planck-Institute for Radio Astronomy)
  • Date : 2022-03-30 10:30 ~ 11:30
  • Location : 온라인 진행 (Online)
  • Host : Thiem Hoang

Magnetic field is believed to play an important role in modern Astrophysics. Dust polarization induced by aligned dust grains is widely used to study magnetic fields in various condition from diffuse medium to star-forming regions. A popular  theory of grain alignment is based on RAdiative Torques (RATs). Recently, suprathermal rotation of dust by RATs is found to induce rotational disruption of large grains into small fragments, which modifies the grain size distribution and affects the dust extinction, emission, and polarization properties. Thus, thermal dust polarization also allows us to study fundamental dust physics (alignment and disruption) and dust properties. In this talk, I will (1) present the recent development of the theory of the grain alignment and disruption by RATs to interpret the polarimetric observations toward molecular cloud w/o embedded sources and PDR regions and applications; (2) introduce the recent works on studying the role of magnetic fields in star-forming regions; (3) discuss the new effect of grain alignment and disruption on surface chemistry; and (4) discuss the future perspectives.