Three-dimensional Simulations of Massive Stars. I. Wave Generation and Propagation

P. V.F. Edelmann, R. P. Ratnasingam, M. G. Pedersen, D. M. Bowman, V. Prat, Tamara Rogers

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We present the first three-dimensional (3D), hydrodynamic simulations of the core convection zone (CZ) and extended radiative zone spanning from 1% to 90% of the stellar radius of an intermediate-mass (3 M) star. This allows us to self-consistently follow the generation of internal gravity waves (IGWs) at the convective boundary and their propagation to the surface.We find that convection in the core is dominated by plumes. The frequency spectrum in the CZ and that of IGW generation is a double power law, as seen in previous two-dimensional (2D) simulations. The spectrum is significantly flatter than theoretical predictions using excitation through Reynolds stresses induced by convective eddies alone. It is compatible with excitation through plume penetration. An empirically determined distribution of plume frequencies generally matches the one necessary to explain a large part of the observed spectrum. We observe waves propagating in the radiation zone and excited standing modes, which can be identified as gravity and fundamental modes. They show similar frequencies and node patterns to those predicted by the stellar oscillation code GYRE. The continuous part of the spectrum fulfills the IGW dispersion relation. A spectrum of tangential velocity and temperature fluctuations close to the surface is extracted, which is directly related to observable brightness variations in stars. Unlike 2D simulations, we do not see the high frequencies associated with wave breaking, likely because the 3D simulations presented in this paper are more heavily damped.

Original languageEnglish (US)
Article number4
JournalAstrophysical Journal
Volume876
Issue number1
DOIs
StatePublished - May 1 2019

Fingerprint

wave generation
massive stars
wave propagation
gravity waves
internal wave
gravity wave
plumes
convection
plume
simulation
stellar oscillations
M stars
wave dispersion
wave breaking
Reynolds stress
excitation
eddy
power law
brightness
penetration

Keywords

  • convection
  • hydrodynamics
  • stars: interiors
  • waves

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Edelmann, P. V. F., Ratnasingam, R. P., Pedersen, M. G., Bowman, D. M., Prat, V., & Rogers, T. (2019). Three-dimensional Simulations of Massive Stars. I. Wave Generation and Propagation. Astrophysical Journal, 876(1), [4]. https://doi.org/10.3847/1538-4357/ab12df

Three-dimensional Simulations of Massive Stars. I. Wave Generation and Propagation. / Edelmann, P. V.F.; Ratnasingam, R. P.; Pedersen, M. G.; Bowman, D. M.; Prat, V.; Rogers, Tamara.

In: Astrophysical Journal, Vol. 876, No. 1, 4, 01.05.2019.

Research output: Contribution to journalArticle

Edelmann, P. V.F. ; Ratnasingam, R. P. ; Pedersen, M. G. ; Bowman, D. M. ; Prat, V. ; Rogers, Tamara. / Three-dimensional Simulations of Massive Stars. I. Wave Generation and Propagation. In: Astrophysical Journal. 2019 ; Vol. 876, No. 1.
@article{8592ff3523704759ae76f3919d2b37c0,
title = "Three-dimensional Simulations of Massive Stars. I. Wave Generation and Propagation",
abstract = "We present the first three-dimensional (3D), hydrodynamic simulations of the core convection zone (CZ) and extended radiative zone spanning from 1{\%} to 90{\%} of the stellar radius of an intermediate-mass (3 M⊙) star. This allows us to self-consistently follow the generation of internal gravity waves (IGWs) at the convective boundary and their propagation to the surface.We find that convection in the core is dominated by plumes. The frequency spectrum in the CZ and that of IGW generation is a double power law, as seen in previous two-dimensional (2D) simulations. The spectrum is significantly flatter than theoretical predictions using excitation through Reynolds stresses induced by convective eddies alone. It is compatible with excitation through plume penetration. An empirically determined distribution of plume frequencies generally matches the one necessary to explain a large part of the observed spectrum. We observe waves propagating in the radiation zone and excited standing modes, which can be identified as gravity and fundamental modes. They show similar frequencies and node patterns to those predicted by the stellar oscillation code GYRE. The continuous part of the spectrum fulfills the IGW dispersion relation. A spectrum of tangential velocity and temperature fluctuations close to the surface is extracted, which is directly related to observable brightness variations in stars. Unlike 2D simulations, we do not see the high frequencies associated with wave breaking, likely because the 3D simulations presented in this paper are more heavily damped.",
keywords = "convection, hydrodynamics, stars: interiors, waves",
author = "Edelmann, {P. V.F.} and Ratnasingam, {R. P.} and Pedersen, {M. G.} and Bowman, {D. M.} and V. Prat and Tamara Rogers",
year = "2019",
month = "5",
day = "1",
doi = "10.3847/1538-4357/ab12df",
language = "English (US)",
volume = "876",
journal = "Astrophysical Journal",
issn = "0004-637X",
publisher = "IOP Publishing Ltd.",
number = "1",

}

TY - JOUR

T1 - Three-dimensional Simulations of Massive Stars. I. Wave Generation and Propagation

AU - Edelmann, P. V.F.

AU - Ratnasingam, R. P.

AU - Pedersen, M. G.

AU - Bowman, D. M.

AU - Prat, V.

AU - Rogers, Tamara

PY - 2019/5/1

Y1 - 2019/5/1

N2 - We present the first three-dimensional (3D), hydrodynamic simulations of the core convection zone (CZ) and extended radiative zone spanning from 1% to 90% of the stellar radius of an intermediate-mass (3 M⊙) star. This allows us to self-consistently follow the generation of internal gravity waves (IGWs) at the convective boundary and their propagation to the surface.We find that convection in the core is dominated by plumes. The frequency spectrum in the CZ and that of IGW generation is a double power law, as seen in previous two-dimensional (2D) simulations. The spectrum is significantly flatter than theoretical predictions using excitation through Reynolds stresses induced by convective eddies alone. It is compatible with excitation through plume penetration. An empirically determined distribution of plume frequencies generally matches the one necessary to explain a large part of the observed spectrum. We observe waves propagating in the radiation zone and excited standing modes, which can be identified as gravity and fundamental modes. They show similar frequencies and node patterns to those predicted by the stellar oscillation code GYRE. The continuous part of the spectrum fulfills the IGW dispersion relation. A spectrum of tangential velocity and temperature fluctuations close to the surface is extracted, which is directly related to observable brightness variations in stars. Unlike 2D simulations, we do not see the high frequencies associated with wave breaking, likely because the 3D simulations presented in this paper are more heavily damped.

AB - We present the first three-dimensional (3D), hydrodynamic simulations of the core convection zone (CZ) and extended radiative zone spanning from 1% to 90% of the stellar radius of an intermediate-mass (3 M⊙) star. This allows us to self-consistently follow the generation of internal gravity waves (IGWs) at the convective boundary and their propagation to the surface.We find that convection in the core is dominated by plumes. The frequency spectrum in the CZ and that of IGW generation is a double power law, as seen in previous two-dimensional (2D) simulations. The spectrum is significantly flatter than theoretical predictions using excitation through Reynolds stresses induced by convective eddies alone. It is compatible with excitation through plume penetration. An empirically determined distribution of plume frequencies generally matches the one necessary to explain a large part of the observed spectrum. We observe waves propagating in the radiation zone and excited standing modes, which can be identified as gravity and fundamental modes. They show similar frequencies and node patterns to those predicted by the stellar oscillation code GYRE. The continuous part of the spectrum fulfills the IGW dispersion relation. A spectrum of tangential velocity and temperature fluctuations close to the surface is extracted, which is directly related to observable brightness variations in stars. Unlike 2D simulations, we do not see the high frequencies associated with wave breaking, likely because the 3D simulations presented in this paper are more heavily damped.

KW - convection

KW - hydrodynamics

KW - stars: interiors

KW - waves

UR - http://www.scopus.com/inward/record.url?scp=85065327300&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85065327300&partnerID=8YFLogxK

U2 - 10.3847/1538-4357/ab12df

DO - 10.3847/1538-4357/ab12df

M3 - Article

AN - SCOPUS:85065327300

VL - 876

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

M1 - 4

ER -