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Title: OUTFLOWS FROM EVOLVED STARS: THE RAPIDLY CHANGING FINGERS OF CRL 618

Our ultimate goal is to probe the nature of the collimator of the outflows in the pre-planetary nebula CRL 618. CRL 618 is uniquely suited for this purpose owing to its multiple, bright, and carefully studied finger-shaped outflows east and west of its nucleus. We compare new Hubble Space Telescope images to images in the same filters observed as much as 11 yr ago to uncover large proper motions and surface brightness changes in its multiple finger-shaped outflows. The expansion age of the ensemble of fingers is close to 100 yr. We find strong brightness variations at the fingertips during the past decade. Deep IR images reveal a multiple ring-like structure of the surrounding medium into which the outflows propagate and interact. Tightly constrained three-dimensional hydrodynamic models link the properties of the fingers to their possible formation histories. We incorporate previously published complementary information to discern whether each of the fingers of CRL 618 are the results of steady, collimated outflows or a brief ejection event that launched a set of bullets about a century ago. Finally, we argue on various physical grounds that fingers of CRL 618 are likely to be the result of a spray of clumps ejectedmore » at the nucleus of CRL 618 since any mechanism that form a sustained set of unaligned jets is unprecedented.« less
Authors:
 [1] ;  [2] ; ;  [3] ;  [4] ;  [5] ;  [6]
  1. Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States)
  2. Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States)
  3. Astronomy Department, University of Texas, Austin, TX 78731-2330 (United States)
  4. Observatorio Astronomico Nacional (IGN), E-28014 Madrid (Spain)
  5. Instituto de Astrofisica de Canarias, E-38200 La Laguna, Tenerife (Spain)
  6. Physics Department, University of Split, Teslina 12/III, HR-21000 Split (Croatia)
Publication Date:
OSTI Identifier:
22121877
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 772; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BRIGHTNESS; COLLIMATORS; EXPANSION; FILTERS; HYDRODYNAMIC MODEL; IMAGES; PLANETARY NEBULAE; PROPER MOTION; STAR EVOLUTION; STARS; TELESCOPES; THREE-DIMENSIONAL CALCULATIONS