{
  "id": "2010.15301",
  "version": "v1",
  "published": "2020-10-29T01:40:14.000Z",
  "updated": "2020-10-29T01:40:14.000Z",
  "title": "Alignment and rotational disruption of dust",
  "authors": [
    "A. Lazarian",
    "Thiem Hoang"
  ],
  "comment": "32 pages, 14 figures. Resubmitted to ApJ after the first referee's report",
  "categories": [
    "astro-ph.GA",
    "astro-ph.EP",
    "astro-ph.SR"
  ],
  "abstract": "We reveal a deep connection between alignment of dust grains by RAdiative torques (RATs) and MEchanical Torques (METs) and rotational disruption of grains introduced by \\cite{Hoangetal:2019}. We establish the preferential disruption of grains aligned with attractor points of high angular momentum (high-J). We introduce {\\it fast alignment} and {\\it fast disruption} for grains that are directly driven to the high-J attractor on a timescale of spin-up, and {\\it slow alignment} and {\\it slow disruption} for grains that are first moved to the low-J attractor and gradually transported to the high-J attractor by gas collisions. We calculate the fraction of grains that experience fast alignment and disruption, denoted by $f_{\\rm high-J}$. The enhancement of grain magnetic susceptibility via iron inclusions expands the parameter space for high-J attractors and increases $f_{\\rm high-J}$. The increase in the magnitude of RATs or METs can increase the efficiency of fast alignment and disruption, but counter-intuitively, decreases the effect of slow alignment and disruption by stronger forcing grains towards low-J attractors, whereas the increase in gas density accelerates disruption by faster transporting grains to the high-J attractor. We also show that disruption induced by RATs and METs depends on the angle between the magnetic field and the anisotropic flow, inducing differences in disruption efficiency of grains at the same distance from the radiation source. We find that pinwheel torques can increase the efficiency of {\\it fast disruption} but may decrease the efficiency of {\\it slow disruption} by delaying the transport of grains from the low-J to high-J attractors via gas collisions. The selective nature of the rotational disruption opens a possibility of observational testing of grain composition as well as physical processes of grain alignment.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-10-29T01:40:14.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "rotational disruption",
      "high-j attractor",
      "fast alignment",
      "gas collisions",
      "fast disruption"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 32,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}