TY - JOUR

T1 - Effects of Rotation and Magnetic Field on the Revival of a Stalled Shock in Supernova Explosions

AU - Fujisawa, Kotaro

AU - Okawa, Hirotada

AU - Yamamoto, Yu

AU - Yamada, Shoichi

N1 - Funding Information:
The authors thank Dr. Kazuya Takahashi and Dr. Wakana Iwakami for helpful discussions. This work was supported by JSPS KAKENHI grant No. 16K17708, 16H03986, 17K18792. K.F. was supported by JSPS Postdoctoral Fellowship for Research Fellowship (16J10223).
Publisher Copyright:
© 2019. The American Astronomical Society. All rights reserved..

PY - 2019

Y1 - 2019

N2 - We investigate axisymmetric steady solutions of (magneto)hydrodynamics equations that approximately describe accretion flows through a standing shock wave onto a protoneutron star and discuss the effects of rotation and magnetic field on the revival of the stalled shock wave in supernova explosions. We develop a new powerful numerical method to calculate the two-dimensional steady accretion flows self-consistently. We first confirm the results of preceding papers that there is a critical luminosity of irradiating neutrinos, above which there exists no steady solution in spherical models. If a collapsing star is rotating and/or has a magnetic field, the accretion flows are no longer spherical owing to the centrifugal force and/or Lorentz force, and the critical luminosity is modified. In fact, we find that the critical luminosity is reduced by about 50%-70% for very rapid rotations; the rotation frequencies are 0.2-0.45 s -1 at the radius of r = 1000 km (equivalent to spin periods ∼0.5-0.22 ms at r = 10 km) and about 20%-50% for strong toroidal magnetic fields (the strengths of which are 1.0 × 10 12 -3.0 × 10 12 G at r = 1000 km), depending on the mass accretion rate. These results may also be interpreted as the existence of a critical specific angular momentum or critical magnetic field, above which there exists no steady solution and the standing shock wave will be revived for a given combination of mass accretion rate and neutrino luminosity.

AB - We investigate axisymmetric steady solutions of (magneto)hydrodynamics equations that approximately describe accretion flows through a standing shock wave onto a protoneutron star and discuss the effects of rotation and magnetic field on the revival of the stalled shock wave in supernova explosions. We develop a new powerful numerical method to calculate the two-dimensional steady accretion flows self-consistently. We first confirm the results of preceding papers that there is a critical luminosity of irradiating neutrinos, above which there exists no steady solution in spherical models. If a collapsing star is rotating and/or has a magnetic field, the accretion flows are no longer spherical owing to the centrifugal force and/or Lorentz force, and the critical luminosity is modified. In fact, we find that the critical luminosity is reduced by about 50%-70% for very rapid rotations; the rotation frequencies are 0.2-0.45 s -1 at the radius of r = 1000 km (equivalent to spin periods ∼0.5-0.22 ms at r = 10 km) and about 20%-50% for strong toroidal magnetic fields (the strengths of which are 1.0 × 10 12 -3.0 × 10 12 G at r = 1000 km), depending on the mass accretion rate. These results may also be interpreted as the existence of a critical specific angular momentum or critical magnetic field, above which there exists no steady solution and the standing shock wave will be revived for a given combination of mass accretion rate and neutrino luminosity.

KW - magnetohydrodynamics (MHD)

KW - methods: numerical

KW - shock waves

KW - stars: magnetic field

KW - stars: rotation

KW - supernovae: general

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U2 - 10.3847/1538-4357/aaffdd

DO - 10.3847/1538-4357/aaffdd

M3 - Article

AN - SCOPUS:85063421921

VL - 872

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 2

M1 - 155

ER -