Constraining differential rotation in gamma Doradus stars from inertial dips properties

Abstract

The presence of dips in the gravity modes period spacing versus period diagram of gamma Doradus stars is now well established by recent asteroseismic studies. Such Lorentzian-shaped inertial dips arise from the interaction of gravito-inertial modes in the radiative envelope of intermediate-mass main sequence stars with pure inertial modes in their convective core. They allow to study stellar internal properties. This window on stellar internal dynamics is extremely valuable in the context of the understanding of angular momentum transport inside stars, since it allows us to probe rotation in their core. We investigate the signature and the detectability of a differential rotation between the convective core and the near-core region inside gamma Doradus stars from the inertial dip properties. We study the coupling between gravito-inertial modes in the radiative zone and pure inertial modes in the convective core in the sub-inertial regime, allowing for a two-zones differential rotation from the two sides of the boundary. Taking a bi-layer rotation profile, we derive the wave equations in the convective core and the radiative envelope. We solve the coupling equation numerically and match the result to an analytical derivation of the Lorentzian dip. We then use typical values of measured near-core rotation and buoyancy travel time to infer ranges of parameters for which differential core to near-core rotation would be detectable in current Kepler data. We show that increasing the convective core rotation with respect to the near-core rotation leads to a shift of the period of the observed dip to lower periods. In addition, the dip gets deeper and thinner as the convective core rotation increases. We demonstrate that such a signature is detectable in Kepler data, given appropriate dip parameter ranges and near-core structural properties.

Submitted to Astronomy & Astrophysics (revised version after the review by the referee), 27 pages, 13 figures, 4 tables. Abstract shortened for arXiv

References in corpus (40)

• Global-Scale Turbulent Convection and Magnetic Dynamo Action in the Solar Envelope
• Slowing the Spins of Stellar Cores
• Probing the properties of convective cores through g modes: high-order g modes in SPB and gamma Doradus stars
• Asteroseismic measurement of surface-to-core rotation in a main sequence A star, KIC 11145123
• The interior rotation of a sample of gamma Doradus stars from ensemble modelling of their gravity mode period spacings
• Simulations of core convection in rotating A-type stars: Magnetic dynamo action
• Asteroseismic measurement of slow, nearly-uniform surface-to-core rotation in the main sequence F star KIC 9244992
• Signatures of internal rotation discovered in the Kepler data of five slowly pulsating B stars
• A new asteroseismic diagnostic for internal rotation in $\gamma$ Doradus stars
• Theory and evidence of global Rossby waves in upper main-sequence stars: r-mode oscillations in many Kepler stars
• Diagnoses to unravel secular hydrodynamical processes in rotating main sequence stars
• The first view of $\delta$ Scuti and $\gamma$ Doradus stars with the TESS mission
• Detecting non-uniform period spacings in the Kepler photometry of gamma Doradus stars: methodology and case studies
• Structural glitches near the cores of red giants revealed by oscillations in g-mode period spacings from stellar models
• Powering Stellar Magnetism: Energy Transfers in Cyclic Dynamos of Sun-like Stars
• The interior angular momentum of core hydrogen burning stars from gravity-mode oscillations
• Gravity modes in rapidly rotating stars. Limits of perturbative methods
• Angular momentum redistribution by mixed modes in evolved low-mass stars. II. Spin-down of the core of red giants induced by mixed modes
• Period spacings of $\gamma$ Doradus pulsators in the \textit{Kepler} field: Rossby and gravity modes in 82 stars
• Can plume-induced internal gravity waves regulate the core rotation of subgiant stars?
• Rotation of the convective core in $\gamma$ Dor stars measured by dips in period spacings of g modes coupled with inertial modes
• The dynamics of the radiative envelope of rapidly rotating stars. I. A spherical Boussinesq model
• Multiple channels for the onset of magnetism in isolated white dwarfs
• Rotation rate of the solar core as a key constraint to magnetic angular momentum transport in stellar interiors
• First evidence of inertial modes in $\gamma$ Doradus stars: The core rotation revealed
• Asteroseismology of evolved stars to constrain the internal transport of angular momentum. I. Efficiency of transport during the subgiant phase
• Period spacings of gravity modes in rapidly rotating magnetic stars I. Axisymmetric fossil field with poloidal and toroidal components
• A model of rotating convection in stellar and planetary interiors: I - convective penetration
• Spin-down by dynamo action in simulated radiative stellar layers
• Internal rotation and inclinations of slowly pulsating B stars: Evidence of interior angular momentum transport
• Predictions for gravity-mode periods and surface abundances in intermediate-mass dwarfs from shear mixing and radiative levitation
• Internal rotation and buoyancy travel time of 60 gamma Doradus stars from uninterrupted TESS light curves spanning 352 days
• Numerical simulations of the Tayler-Spruit dynamo in proto-magnetars
• Asteroseismology of the dip structure in period-spacings of rapidly rotating gamma Doradus stars caused by the coupling between core and envelope oscillations
• Improved Asymptotic Expressions for the Eigenvalues of Laplace's Tidal Equations
• The complex interplay between tidal inertial waves and zonal flows in differentially rotating stellar and planetary convective regions I. Free waves
• Buoyancy glitches in pulsating stars revisited
• Angular momentum transport near convective-core boundaries of Gamma Doradus stars
• Mode coupling coefficients between the convective core and radiative envelope of $\gamma$Doradus and slowly pulsating B stars
• Properties of observable mixed inertial and gravito-inertial modes in γ Doradus stars

Cited by in corpus (3)

• Exploring the probing power of gamma-Dor's inertial dip for core magnetism: case of a toroidal field
• Core-envelope coupling of gravito-inertial waves in pre-main-sequence solar-type stars
• From core to envelope: revealing the deep dynamics of stars with two convective zones