Probing core overshooting using subgiant asteroseismology: the case of KIC10273246

Abstract

The size of convective cores remains uncertain, despite its substantial influence on stellar evolution, and thus on stellar ages. The seismic modeling of young subgiants can be used to obtain indirect constraints on the core structure during main sequence, thanks to the high probing potential of mixed modes. We selected the young subgiant KIC10273246, observed by Kepler, based on its mixed-mode properties. We thoroughly modeled this star, with the aim of placing constraints on the size of its main sequence convective core. We first extracted the parameters of the oscillation modes of the star using the full Kepler data set. To overcome the challenges posed by the seismic modeling of subgiants, we proposed a method which is specifically tailored for subgiants with mixed modes and consists in a nested optimization. We then applied this method to perform a detailed seismic modeling of KIC10273246. We obtained models that show good statistical agreements with the observations, both seismic and non-seismic. We showed that including core overshooting in the models significantly improves the quality of the seismic fit, optimal models being found for ${\alpha }_{\mathrm{ov}}=0.15$. Higher amounts of core overshooting strongly worsen the agreement with the observations and are thus firmly ruled out. We also found that having access to two g-dominated mixed modes in young subgiants allows us to place stronger constraints on the gradient of molecular weight in the core and on the central density. This study confirms the high potential of young subgiants with mixed modes to investigate the size of main-sequence convective cores. It paves the way for a more general study including the subgiants observed with Kepler, TESS, and eventually PLATO.

arXiv commentAccepted in A&A, 15 pages, 15 figures. Second version corrects language and Fig. 8, which was erroneous

References in corpus (49)

• The chemical composition of the Sun
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• Modules for Experiments in Stellar Astrophysics (MESA): Binaries, Pulsations, and Explosions
• The Galaxy Evolution Explorer: A Space Ultraviolet Survey Mission
• Modules for Experiments in Stellar Astrophysics (MESA): Convective Boundaries, Element Diffusion, and Massive Star Explosions
• A 3D Dust Map Based on Gaia, Pan-STARRS 1 and 2MASS
• The PLATO 2.0 Mission
• Gaia Data Release 2: Photometric content and validation
• The Victoria-Regina Stellar Models: Evolutionary Tracks and Isochrones for a Wide Range in Mass and Metallicity that Allow for Empirically Constrained Amounts of Convective Core Overshooting
• ADIPLS -- the Aarhus adiabatic oscillation package
• Seismic constraints on the radial dependence of the internal rotation profiles of six Kepler subgiants and young red giants
• Initial Characteristics of Kepler Long Cadence Data For Detecting Transiting Planets
• Preparation of Kepler lightcurves for asteroseismic analyses
• Probing the core structure and evolution of red giants using gravity-dominated mixed modes observed with Kepler
• The underlying physical meaning of the ${\nu }_{\max }-{\nu }_{\mathrm{c}}$ relation
• A new correction of stellar oscillation frequencies for near-surface effects
• Eclipsing Binary Stars as Benchmarks for Trigonometric Parallaxes in the Gaia Era
• Accurate fundamental parameters for Lower Main Sequence Stars
• Tight asteroseismic constraints on core overshooting and diffusive mixing in the slowly rotating pulsating B8.3V star KIC 10526294
• Seismic evidence for a weak radial differential rotation in intermediate-mass core helium burning stars
• Confirmation of the $Gaia$ DR2 parallax zero-point offset using asteroseismology and spectroscopy in the $Kepler$ field
• Asteroseismology for "à la carte" stellar age-dating and weighing: Age and mass of the CoRoT exoplanet host HD 52265
• Sub-Inertial Gravity Modes in the B8V Star KIC 7760680 Reveal Moderate Core Overshooting and Low Vertical Diffusive Mixing
• Asymptotic and measured large frequency separations
• Stellar ages and convective cores in field main-sequence stars: first asteroseismic application to two Kepler targets
• Measuring the extent of convective cores in low-mass stars using Kepler data: towards a calibration of core overshooting
• Nearly-uniform internal rotation of solar-like main-sequence stars revealed by space-based asteroseismology and spectroscopic measurements
• Constraints on the structure of the core of subgiants via mixed modes: the case of HD49385
• Oscillating K giants with the WIRE satellite: determination of their asteroseismic masses
• AIMS - A new tool for stellar parameter determinations using asteroseismic constraints
• A Hot Saturn Orbiting An Oscillating Late Subgiant Discovered by TESS
• On the proper use of the Schwarzschild and Ledoux criteria in stellar evolution computations
• The dependence of convective core overshooting on stellar mass: reality check, and additional evidence
• The Chemical Evolution of Helium
• Impacts of radiative accelerations on solar-like oscillating main-sequence stars
• Evolution of Deuterium, 3He and 4He in the Galaxy
• Asteroseismology from multi-month Kepler photometry: the evolved Sun-like stars KIC 10273246 and KIC 10920273
• Seismic evidence for near solid-body rotation in two Kepler subgiants and implications for angular momentum transport
• Observations of intensity fluctuations attributed to granulation and faculae on Sun-like stars from the Kepler mission
• Fundamental properties of five Kepler stars using global asteroseismic quantities and ground-based observations
• Constraining differential rotation of Sun-like stars from asteroseismic and starspot rotation periods
• Asteroseismology of 36 Kepler subgiants -- II: Determining ages from detailed modelling
• Survival of a convective core in low-mass solar-like pulsator HD 203608
• Significant uncertainties from calibrating overshooting with eclipsing binary systems
• The Evolution of Rotation and Magnetic Activity in 94 Aqr Aa from Asteroseismology with TESS
• The subgiant HR 7322 as an asteroseismic benchmark star
• Asteroseismic modelling of the subgiant μ Herculis using SONG data: lifting the degeneracy between age and model input parameters
• Constraints on the core mu-gradient of the solar-like star HD 49385 via low-degree mixed modes
• Open issues in probing interiors of solar-like oscillating main sequence stars: 2. Diversity in the HR diagram

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• PARSEC V2.0: Stellar tracks and isochrones of low and intermediate mass stars with rotation
• 3D hydrodynamic simulations of massive main-sequence stars. I. Dynamics and mixing of convection and internal gravity waves
• Mixed Modes and Asteroseismic Surface Effects: II. Subgiant Systematics
• Properties of the ionisation glitch: I. Modelling the ionisation region
• Asteroseismology of evolved stars with EGGMiMoSA I. Theoretical mixed-mode patterns from the subgiant to the RGB phase
• Multi-cavity gravito-acoustic modes in stars: A general analytical resonance condition
• Impact of central mixing scheme and nuclear reaction network on the extent of convective cores
• Core overshoot constrained by the absence of a solar convective core and some solar-like stars
• Asteroseismic investigation on KIC 10526294 to probe convective core overshoot mixing
• Coralie radial velocity search for companions around evolved stars (CASCADES) II. Seismic masses for three red giants orbited by long-period massive planets
• Asteroseismology of the young open cluster NGC 2516 II. Constraining cluster age using gravity-mode pulsators
• Mixing due to internal gravity waves can explain the CNO surface abundances of B-type detached eclipsing binaries and single stars
• Properties of the ionisation glitch II. Seismic signature of the structural perturbation
• Constraining the Rotation Profile in a Low-Luminosity Subgiant with a Surface Rotation Measurement
• Is there a unique asteroseismic interior model for the solar-like oscillating KIC 7747078?
• Detailed theoretical analysis of core Helium-burning stars: Mixed mode patterns I. Impact of the He-flash discontinuity and of induced semi-convection
• One size does not fit all: Evidence for a range of mixing efficiencies in stellar evolution calculations