Presupernova evolution of rotating massive stars. I. Numerical method and evolution of the internal stellar structure

A. Heger, N. Langer, S. E. Woosley

Research output: Contribution to journalArticleResearchpeer-review

Abstract

The evolution of rotating stars with zero-age main-sequence (ZAMS) masses in the range 8-25 M is followed through all stages of stable evolution. The initial angular momentum is chosen such that the star's equatorial rotational velocity on the ZAMS ranges from zero to ∼70% of breakup. The stars rotate rigidly on the ZAMS as a consequence of angular momentum redistribution during the pre-main-sequence evolution. Redistribution of angular momentum and chemical species are then followed as a consequence of Eddington-Sweet circulation, Solberg-Høiland instability, the Goldreich-Schubert-Fricke instability, and secular and dynamic shear instability. The effects of the centrifugal force on the stellar structure are included. Convectively unstable zones are assumed to tend toward rigid rotation, and uncertain mixing efficiencies are gauged by observations. We find, as noted in previous work, that rotation increases the helium core masses and enriches the stellar envelopes with products of hydrogen burning. We determine, for the first time, the angular momentum distribution in typical presupernova stars along with their detailed chemical structure. Angular momentum loss due to (nonmagnetic) stellar winds and the redistribution of angular momentum during core hydrogen burning are of crucial importance for the specific angular momentum of the core. Neglecting magnetic fields, we find angular momentum transport from the core to the envelope to be unimportant after core helium burning. We obtain specific angular momenta for the iron core and overlying material of 1016-1017 cm2 s-1. These values are insensitive to the initial angular momentum and to uncertainties in the efficiencies of rotational mixing. They are small enough to avoid triaxial deformations of the iron core before it collapses, but could lead to neutron stars which rotate close to breakup. They are also in the range required for the collapsar model of gamma-ray bursts. The apparent discrepancy with the measured rotation rates of young pulsars is discussed.

Original languageEnglish
Pages (from-to)368-396
Number of pages29
JournalAstrophysical Journal
Volume528
Issue number1 PART 1
Publication statusPublished - 1 Jan 2000
Externally publishedYes

Keywords

  • Hydrodynamics
  • Methods: numerical
  • Stars early-type
  • Stars rotation
  • Stars: evolution
  • Stars: interiors

Cite this

@article{64d7438de0154c33a1aebfb667223d92,
title = "Presupernova evolution of rotating massive stars. I. Numerical method and evolution of the internal stellar structure",
abstract = "The evolution of rotating stars with zero-age main-sequence (ZAMS) masses in the range 8-25 M⊙ is followed through all stages of stable evolution. The initial angular momentum is chosen such that the star's equatorial rotational velocity on the ZAMS ranges from zero to ∼70{\%} of breakup. The stars rotate rigidly on the ZAMS as a consequence of angular momentum redistribution during the pre-main-sequence evolution. Redistribution of angular momentum and chemical species are then followed as a consequence of Eddington-Sweet circulation, Solberg-H{\o}iland instability, the Goldreich-Schubert-Fricke instability, and secular and dynamic shear instability. The effects of the centrifugal force on the stellar structure are included. Convectively unstable zones are assumed to tend toward rigid rotation, and uncertain mixing efficiencies are gauged by observations. We find, as noted in previous work, that rotation increases the helium core masses and enriches the stellar envelopes with products of hydrogen burning. We determine, for the first time, the angular momentum distribution in typical presupernova stars along with their detailed chemical structure. Angular momentum loss due to (nonmagnetic) stellar winds and the redistribution of angular momentum during core hydrogen burning are of crucial importance for the specific angular momentum of the core. Neglecting magnetic fields, we find angular momentum transport from the core to the envelope to be unimportant after core helium burning. We obtain specific angular momenta for the iron core and overlying material of 1016-1017 cm2 s-1. These values are insensitive to the initial angular momentum and to uncertainties in the efficiencies of rotational mixing. They are small enough to avoid triaxial deformations of the iron core before it collapses, but could lead to neutron stars which rotate close to breakup. They are also in the range required for the collapsar model of gamma-ray bursts. The apparent discrepancy with the measured rotation rates of young pulsars is discussed.",
keywords = "Hydrodynamics, Methods: numerical, Stars early-type, Stars rotation, Stars: evolution, Stars: interiors",
author = "A. Heger and N. Langer and Woosley, {S. E.}",
year = "2000",
month = "1",
day = "1",
language = "English",
volume = "528",
pages = "368--396",
journal = "The Astrophysical Journal",
issn = "0004-637X",
publisher = "American Astronomical Society",
number = "1 PART 1",

}

Presupernova evolution of rotating massive stars. I. Numerical method and evolution of the internal stellar structure. / Heger, A.; Langer, N.; Woosley, S. E.

In: Astrophysical Journal, Vol. 528, No. 1 PART 1, 01.01.2000, p. 368-396.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Presupernova evolution of rotating massive stars. I. Numerical method and evolution of the internal stellar structure

AU - Heger, A.

AU - Langer, N.

AU - Woosley, S. E.

PY - 2000/1/1

Y1 - 2000/1/1

N2 - The evolution of rotating stars with zero-age main-sequence (ZAMS) masses in the range 8-25 M⊙ is followed through all stages of stable evolution. The initial angular momentum is chosen such that the star's equatorial rotational velocity on the ZAMS ranges from zero to ∼70% of breakup. The stars rotate rigidly on the ZAMS as a consequence of angular momentum redistribution during the pre-main-sequence evolution. Redistribution of angular momentum and chemical species are then followed as a consequence of Eddington-Sweet circulation, Solberg-Høiland instability, the Goldreich-Schubert-Fricke instability, and secular and dynamic shear instability. The effects of the centrifugal force on the stellar structure are included. Convectively unstable zones are assumed to tend toward rigid rotation, and uncertain mixing efficiencies are gauged by observations. We find, as noted in previous work, that rotation increases the helium core masses and enriches the stellar envelopes with products of hydrogen burning. We determine, for the first time, the angular momentum distribution in typical presupernova stars along with their detailed chemical structure. Angular momentum loss due to (nonmagnetic) stellar winds and the redistribution of angular momentum during core hydrogen burning are of crucial importance for the specific angular momentum of the core. Neglecting magnetic fields, we find angular momentum transport from the core to the envelope to be unimportant after core helium burning. We obtain specific angular momenta for the iron core and overlying material of 1016-1017 cm2 s-1. These values are insensitive to the initial angular momentum and to uncertainties in the efficiencies of rotational mixing. They are small enough to avoid triaxial deformations of the iron core before it collapses, but could lead to neutron stars which rotate close to breakup. They are also in the range required for the collapsar model of gamma-ray bursts. The apparent discrepancy with the measured rotation rates of young pulsars is discussed.

AB - The evolution of rotating stars with zero-age main-sequence (ZAMS) masses in the range 8-25 M⊙ is followed through all stages of stable evolution. The initial angular momentum is chosen such that the star's equatorial rotational velocity on the ZAMS ranges from zero to ∼70% of breakup. The stars rotate rigidly on the ZAMS as a consequence of angular momentum redistribution during the pre-main-sequence evolution. Redistribution of angular momentum and chemical species are then followed as a consequence of Eddington-Sweet circulation, Solberg-Høiland instability, the Goldreich-Schubert-Fricke instability, and secular and dynamic shear instability. The effects of the centrifugal force on the stellar structure are included. Convectively unstable zones are assumed to tend toward rigid rotation, and uncertain mixing efficiencies are gauged by observations. We find, as noted in previous work, that rotation increases the helium core masses and enriches the stellar envelopes with products of hydrogen burning. We determine, for the first time, the angular momentum distribution in typical presupernova stars along with their detailed chemical structure. Angular momentum loss due to (nonmagnetic) stellar winds and the redistribution of angular momentum during core hydrogen burning are of crucial importance for the specific angular momentum of the core. Neglecting magnetic fields, we find angular momentum transport from the core to the envelope to be unimportant after core helium burning. We obtain specific angular momenta for the iron core and overlying material of 1016-1017 cm2 s-1. These values are insensitive to the initial angular momentum and to uncertainties in the efficiencies of rotational mixing. They are small enough to avoid triaxial deformations of the iron core before it collapses, but could lead to neutron stars which rotate close to breakup. They are also in the range required for the collapsar model of gamma-ray bursts. The apparent discrepancy with the measured rotation rates of young pulsars is discussed.

KW - Hydrodynamics

KW - Methods: numerical

KW - Stars early-type

KW - Stars rotation

KW - Stars: evolution

KW - Stars: interiors

UR - http://www.scopus.com/inward/record.url?scp=0034424128&partnerID=8YFLogxK

M3 - Article

VL - 528

SP - 368

EP - 396

JO - The Astrophysical Journal

JF - The Astrophysical Journal

SN - 0004-637X

IS - 1 PART 1

ER -