Three-dimensional Simulations of Massive Stars. II. Age Dependence

We present 3D full star simulations, reaching up to 90% of the total stellar radius, for three 7 M ⊙ stars of different ages: zero-age main sequence (ZAMS), mid–main sequence (midMS), and terminal-age main sequence (TAMS). A comparison with several theoretical prescriptions shows that the generation spectra for all three ages are dominated by convective plumes. Two distinct overshooting layers are observed, with most plumes stopped within the layer situated directly above the convective boundary; overshooting to the second, deeper layer becomes progressively more infrequent with increasing stellar age. Internal gravity wave (IGW) propagation is significantly impacted in the midMS and TAMS models as a result of some IGWs getting trapped within their Brunt–Väisälä frequency spikes. A fundamental change in the wave structure across radius is also observed, driven by the effect of density stratification on IGW propagation causing waves to become evanescent within the radiative zone, with older stars being affected more strongly. We find that the steepness of the frequency spectrum at the surface increases from ZAMS to the older models, with older stars also showing more modes in their spectra.

[1]  I. Baraffe,et al.  Two-dimensional simulations of internal gravity waves in a 5 M⊙ zero-age-main-sequence model , 2023, Monthly Notices of the Royal Astronomical Society.

[2]  J. Krtička,et al.  Stochastic light variations in hot stars from wind instability: finding photometric signatures and testing against the TESS data , 2021, 2103.08755.

[3]  P. Edelmann,et al.  Two-dimensional simulations of internal gravity waves in the radiation zones of intermediate-mass stars , 2020, 2008.03306.

[4]  C. Aerts,et al.  Fully compressible simulations of waves and core convection in main-sequence stars , 2020, Astronomy & Astrophysics.

[5]  C. Aerts,et al.  Photometric detection of internal gravity waves in upper main-sequence stars , 2020, Astronomy & Astrophysics.

[6]  E. Quataert,et al.  Low-frequency Variability in Massive Stars: Core Generation or Surface Phenomenon? , 2019, The Astrophysical Journal.

[7]  C. Aerts,et al.  Low-frequency gravity waves in blue supergiants revealed by high-precision space photometry , 2019, Nature Astronomy.

[8]  V. Prat,et al.  Three-dimensional Simulations of Massive Stars. I. Wave Generation and Propagation , 2019, The Astrophysical Journal.

[9]  G. Meynet,et al.  Asteroseismology of evolved stars to constrain the internal transport of angular momentum , 2018, Astronomy & Astrophysics.

[10]  C. Aerts,et al.  Photometric detection of internal gravity waves in upper main-sequence stars , 2018, Astronomy & Astrophysics.

[11]  P. Edelmann,et al.  Onset of non-linear internal gravity waves in intermediate-mass stars , 2018, Monthly Notices of the Royal Astronomical Society.

[12]  C. Aerts,et al.  Angular Momentum Transport in Stellar Interiors , 2018, Annual Review of Astronomy and Astrophysics.

[13]  C. Aerts,et al.  Sensitivity of gravito-inertial modes to differential rotation in intermediate-mass main-sequence stars , 2018, Astronomy & Astrophysics.

[14]  U. California,et al.  Angular momentum transport by heat-driven g-modes in slowly pulsating B stars , 2017, 1712.02420.

[15]  F. Timmes,et al.  Modules for Experiments in Stellar Astrophysics ( ): Convective Boundaries, Element Diffusion, and Massive Star Explosions , 2017, 1710.08424.

[16]  C. Aerts,et al.  The Interior Angular Momentum of Core Hydrogen Burning Stars from Gravity-mode Oscillations , 2017, 1709.01874.

[17]  M. Popov,et al.  Extreme value statistics for two-dimensional convective penetration in a pre-Main Sequence star , 2017, 1706.04852.

[18]  J. Fuller.  Heartbeat stars, tidally excited oscillations and resonance locking , 2017, 1706.05054.

[19]  K. Belkacem,et al.  Can plume-induced internal gravity waves regulate the core rotation of subgiant stars? , 2017, 1705.10101.

[20]  M. Popov,et al.  Spherical-shell boundaries for two-dimensional compressible convection in a star , 2016, 1606.07200.

[21]  K. Belkacem,et al.  Generation of internal gravity waves by penetrative convection , 2015, 1512.07028.

[22]  Dean M. Townsley,et al.  MODULES FOR EXPERIMENTS IN STELLAR ASTROPHYSICS (MESA): BINARIES, PULSATIONS, AND EXPLOSIONS , 2015, 1506.03146.

[23]  B. Mosser,et al.  Angular momentum redistribution by mixed modes in evolved low-mass stars. II. Spin-down of the core of red giants induced by mixed modes , 2015, 1505.05452.

[24]  B. Mosser,et al.  Angular momentum redistribution by mixed modes in evolved low-mass stars. I. Theoretical formalism , 2015, 1505.05447.

[25]  F. Spada,et al.  The angular momentum transport by unstable toroidal magnetic fields , 2014, 1404.4288.

[26]  S. Mathis,et al.  Theoretical seismology in 3D: nonlinear simulations of internal gravity waves in solar-like stars , 2014, 1403.4052.

[27]  R. Townsend,et al.  GYRE: An open-source stellar oscillation code based on a new Magnus Multiple Shooting Scheme , 2013, 1308.2965.

[28]  P. Eggenberger,et al.  Understanding angular momentum transport in red giants: the case of KIC 7341231 , 2013, Astronomy & Astrophysics.

[29]  S. Mathis,et al.  Coupling between internal waves and shear-induced turbulence in stellar radiation zones: the critical layers , 2013, 1303.1715.

[30]  M. H. Montgomery,et al.  MODULES FOR EXPERIMENTS IN STELLAR ASTROPHYSICS (MESA): PLANETS, OSCILLATIONS, ROTATION, AND MASSIVE STARS , 2013, 1301.0319.

[31]  C. Meakin,et al.  TURBULENT CONVECTION IN STELLAR INTERIORS. III. MEAN-FIELD ANALYSIS AND STRATIFICATION EFFECTS , 2012, 1212.6365.

[32]  E. Quataert,et al.  Internal gravity wave excitation by turbulent convection , 2012, 1210.4547.

[33]  P. Eggenberger,et al.  Angular momentum transport in stellar interiors constrained by rotational splittings of mixed modes in red giants , 2012, 1207.1023.

[34]  G. Handler.  Asteroseismology , 2012, 1205.6407.

[35]  E. Quataert,et al.  Wave‐driven mass loss in the last year of stellar evolution: setting the stage for the most luminous core‐collapse supernovae , 2012, 1202.5036.

[36]  Paul G. Beck,et al.  Fast core rotation in red-giant stars as revealed by gravity-dominated mixed modes , 2011, Nature.

[37]  K. Macgregor,et al.  On the Interaction of Internal Gravity Waves with Magnetic Field II. Convective Forcing , 2010, 1009.5933.

[38]  Frank Timmes,et al.  MODULES FOR EXPERIMENTS IN STELLAR ASTROPHYSICS (MESA) , 2010, 1009.1622.

[39]  L. Deng,et al.  Numerical simulations of downward convective overshooting in giants , 2009, 1603.01690.

[40]  N. Langer,et al.  Sub-surface convection zones in hot massive stars and their observable consequences , 2009, 0903.2049.

[41]  M. Pinsonneault,et al.  What Prevents Internal Gravity Waves from Disturbing the Solar Uniform Rotation? , 2008, 0801.3622.

[42]  J. Fernandes,et al.  On the effect of overshooting as predicted by the modelling of the pre-main-sequence evolution of a 2 M⊙ star , 2006, astro-ph/0606029.

[43]  G. Glatzmaier,et al.  Numerical Simulations of Penetration and Overshoot in the Sun , 2006, astro-ph/0601668.

[44]  G. Glatzmaier,et al.  Gravity waves in the Sun , 2005, astro-ph/0508560.

[45]  C. Charbonnel,et al.  Hydrodynamical stellar models including rotation, internal gravity waves and atomic diffusion. I. Formalism and tests on Pop I dwarfs , 2005, astro-ph/0505229.

[46]  S. Woosley,et al.  Presupernova Evolution of Differentially Rotating Massive Stars Including Magnetic Fields , 2004, astro-ph/0409422.

[47]  S. Mathis,et al.  Transport and mixing in the radiation zones of rotating stars. I. Hydrodynamical processes , 2004, astro-ph/0406418.

[48]  J. Toomre,et al.  Simulations of Core Convection in Rotating A-Type Stars: Differential Rotation and Overshooting , 2003, astro-ph/0310003.

[49]  K. Petrovay,et al.  A new model for the lower overshoot layer in the Sun , 2002, astro-ph/0307534.

[50]  J. Zahn,et al.  Angular Momentum Extraction by Gravity Waves in the Sun , 2002, astro-ph/0206479.

[51]  H. Spruit.  Dynamo action by differential rotation in a stably stratified stellar interior , 2001, astro-ph/0108207.

[52]  J. Zahn,et al.  Angular Momentum Redistribution by Waves in the Sun , 1999, astro-ph/9902309.

[53]  P. Roberts,et al.  Equations governing convection in earth's core and the geodynamo , 1995 .

[54]  J. Toomre,et al.  Penetration below a convective zone , 1994 .

[55]  H. Spruit,et al.  Li depletion in F stars by internal gravity waves , 1991 .

[56]  Pawan Kumar,et al.  Wave generation by turbulent convection , 1990 .

[57]  Hiroyasu Ando,et al.  Nonradial Oscillations of Stars , 1989 .

[58]  J. Toomre,et al.  Nonlinear compressible convection penetrating into stable layers and producing internal gravity waves , 1986 .

[59]  Gary A. Glatzmaier,et al.  Numerical Simulations of Stellar Convective Dynamos. I. The Model and Method , 1984 .

[60]  W. Press.  Radiative and other effects from internal waves in solar and stellar interiors , 1981 .

[61]  M. Lighthill.  On sound generated aerodynamically I. General theory , 1952, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[62]  K. Macgregor,et al.  On the interaction of internal gravity waves with a magnetic field ― I. Artificial wave forcing , 2010 .

[63]  JOHN EVANS,et al.  The Royal Society , 1894, Nature.

[64]  Paul R. Woodward,et al.  Three-dimensional Simulations of Turbulent Compressible Convection , 2000 .