Linear analysis on the growth of non-spherical perturbations in supersonic accretion flows

Kazuya Takahashi, Shoichi Yamada

    Research output: Contribution to journalArticle

    10 Citations (Scopus)

    Abstract

    We analyzed the growth of non-spherical perturbations in supersonic accretion flows. We have in mind an application to the post-bounce phase of core-collapse supernovae (CCSNe). Such non-spherical perturbations have been suggested by a series of papers by Arnett, who has numerically investigated violent convections in the outer layers of pre-collapse stars. Moreover, Couch & Ott demonstrated in their numerical simulations that such perturbations may lead to a successful supernova even for a progenitor that fails to explode without fluctuations. This study investigated the linear growth of perturbations during the infall onto a stalled shock wave. The linearized equations are solved as an initial and boundary value problem with the use of a Laplace transform. The background is a Bondi accretion flow whose parameters are chosen to mimic the 15 M progenitor model by Woosley & Heger, which is supposed to be a typical progenitor of CCSNe. We found that the perturbations that are given at a large radius grow as they flow down to the shock radius; the density perturbations can be amplified by a factor of 30, for example. We analytically show that the growth rate is proportional to l, the index of the spherical harmonics. We also found that the perturbations oscillate in time with frequencies that are similar to those of the standing accretion shock instability. This may have an implication for shock revival in CCSNe, which will be investigated in our forthcoming paper in more detail.

    Original languageEnglish
    Article number162
    JournalAstrophysical Journal
    Volume794
    Issue number2
    DOIs
    Publication statusPublished - 2014 Oct 20

    Fingerprint

    accretion
    perturbation
    supernovae
    shock
    boundary value problems
    couches
    Laplace transform
    radii
    spherical harmonics
    analysis
    shock wave
    shock waves
    convection
    stars
    simulation

    Keywords

    • methods: analytical
    • supernovae: general

    ASJC Scopus subject areas

    • Space and Planetary Science
    • Astronomy and Astrophysics

    Cite this

    Linear analysis on the growth of non-spherical perturbations in supersonic accretion flows. / Takahashi, Kazuya; Yamada, Shoichi.

    In: Astrophysical Journal, Vol. 794, No. 2, 162, 20.10.2014.

    Research output: Contribution to journalArticle

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