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Title: The Shock Dynamics of Heterogeneous YSO Jets: 3D Simulations Meet Multi-epoch Observations

Abstract

High-resolution observations of young stellar object (YSO) jets show them to be composed of many small-scale knots or clumps. In this paper, we report results of 3D numerical simulations designed to study how such clumps interact and create morphologies and kinematic patterns seen in emission line observations. Our simulations focus on clump scale dynamics by imposing velocity differences between spherical, over-dense regions, which then lead to the formation of bow shocks as faster clumps overtake slower material. We show that much of the spatial structure apparent in emission line images of jets arises from the dynamics and interactions of these bow shocks. Our simulations show a variety of time-dependent features, including bright knots associated with Mach stems where the shocks intersect, a “frothy” emission structure that arises from the presence of the Nonlinear Thin Shell Instability along the surfaces of the bow shocks, and the merging and fragmentation of clumps. Our simulations use a new non-equilibrium cooling method to produce synthetic emission maps in H α and [S ii]. These are directly compared to multi-epoch Hubble Space Telescope observations of Herbig–Haro jets. We find excellent agreement between features seen in the simulations and the observations in terms of both propermore » motion and morphologies. Thus we conclude that YSO jets may be dominated by heterogeneous structures and that interactions between these structures and the shocks they produce can account for many details of YSO jet evolution.« less

Authors:
;  [1];  [2];  [3]
  1. Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627-0171 (United States)
  2. Department of Physics and Astronomy, Rice University, 6100 S. Main, Houston, TX 77521-1892 (United States)
  3. Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom)
Publication Date:
OSTI Identifier:
22661287
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 837; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; EMISSION; EQUILIBRIUM; EVOLUTION; FRAGMENTATION; HERBIG-HARO OBJECTS; HYDRODYNAMICS; INSTABILITY; INTERACTIONS; NONLINEAR PROBLEMS; PROPER MOTION; RESOLUTION; SHOCK WAVES; SPACE; STARS; SURFACES; TELESCOPES; TIME DEPENDENCE

Citation Formats

Hansen, E. C., Frank, A., Hartigan, P., and Lebedev, S. V. The Shock Dynamics of Heterogeneous YSO Jets: 3D Simulations Meet Multi-epoch Observations. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA5CA8.
Hansen, E. C., Frank, A., Hartigan, P., & Lebedev, S. V. The Shock Dynamics of Heterogeneous YSO Jets: 3D Simulations Meet Multi-epoch Observations. United States. doi:10.3847/1538-4357/AA5CA8.
Hansen, E. C., Frank, A., Hartigan, P., and Lebedev, S. V. Fri . "The Shock Dynamics of Heterogeneous YSO Jets: 3D Simulations Meet Multi-epoch Observations". United States. doi:10.3847/1538-4357/AA5CA8.
@article{osti_22661287,
title = {The Shock Dynamics of Heterogeneous YSO Jets: 3D Simulations Meet Multi-epoch Observations},
author = {Hansen, E. C. and Frank, A. and Hartigan, P. and Lebedev, S. V.},
abstractNote = {High-resolution observations of young stellar object (YSO) jets show them to be composed of many small-scale knots or clumps. In this paper, we report results of 3D numerical simulations designed to study how such clumps interact and create morphologies and kinematic patterns seen in emission line observations. Our simulations focus on clump scale dynamics by imposing velocity differences between spherical, over-dense regions, which then lead to the formation of bow shocks as faster clumps overtake slower material. We show that much of the spatial structure apparent in emission line images of jets arises from the dynamics and interactions of these bow shocks. Our simulations show a variety of time-dependent features, including bright knots associated with Mach stems where the shocks intersect, a “frothy” emission structure that arises from the presence of the Nonlinear Thin Shell Instability along the surfaces of the bow shocks, and the merging and fragmentation of clumps. Our simulations use a new non-equilibrium cooling method to produce synthetic emission maps in H α and [S ii]. These are directly compared to multi-epoch Hubble Space Telescope observations of Herbig–Haro jets. We find excellent agreement between features seen in the simulations and the observations in terms of both proper motion and morphologies. Thus we conclude that YSO jets may be dominated by heterogeneous structures and that interactions between these structures and the shocks they produce can account for many details of YSO jet evolution.},
doi = {10.3847/1538-4357/AA5CA8},
journal = {Astrophysical Journal},
number = 2,
volume = 837,
place = {United States},
year = {Fri Mar 10 00:00:00 EST 2017},
month = {Fri Mar 10 00:00:00 EST 2017}
}