Fundamental properties of a selected sample of Ap stars: Inferences from interferometric and asteroseismic constraints

Abstract

Magnetic fields influence the formation and evolution of stars and impact the observed stellar properties. Ap stars (magnetic A-type stars) are a prime example of this. Access to precise and accurate determinations of their stellar fundamental properties, such as masses and ages, is crucial to understand the origin and evolution of fossil magnetic fields. We propose using the radii and luminosities determined from interferometric measurements, in addition to seismic constraints when available, to infer fundamental properties of 14 Ap stars préviously characterised. We used a grid-based modelling approach, employing stellar models computed with the \textsc{cestam} stellar evolution code, and the parameter search performed with the \textsc{aims} optimisation method. The stellar model grid was built using a wide range of initial helium abundances and metallicities in order to avoid any bias originating from the initial chemical composition. The large frequency separations ($\Delta \nu$) of HR\,1217 (HD\,24712) and $\alpha$~Cir (HD\,128898), two rapidly oscillating Ap stars of the sample, were used as seismic constraints. We inferred the fundamental properties of the 14 stars in the sample. The overall results are consistent within $1\sigma$ with previous studies, however, the stellar masses inferred in this study are higher. This trend likely originates from the broader range of chemical compositions considered in this work. We show that the use of $\Delta \nu$ in the modelling significantly improves our inferences, allowing us to set reasonable constraints on the initial metallicity which is, otherwise, unconstrained. This gives an indication of the efficiency of atomic diffusion in the atmospheres of roAp stars and opens the possibility of characterising the transport of chemical elements in their interiors.

arXiv comment19 pages, 14 figures, accepted for publication in A&A

References in corpus (75)

• The chemical composition of the Sun
• Gaia Data Release 2. Summary of the contents and survey properties
• Modules for Experiments in Stellar Astrophysics (MESA)
• Validation of the new Hipparcos reduction
• Modules for Experiments in Stellar Astrophysics (MESA): Giant Planets, Oscillations, Rotation, and Massive Stars
• Modules for Experiments in Stellar Astrophysics (MESA): Binaries, Pulsations, and Explosions
• Modules for Experiments in Stellar Astrophysics (MESA): Convective Boundaries, Element Diffusion, and Massive Star Explosions
• Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
• Low Temperature Opacities
• Magnetic fields of non-degenerate stars
• Dynamical Simulations of Magnetically Channeled Line-Driven Stellar Winds: I. Isothermal, Nonrotating, Radially Driven Flow
• ADIPLS -- the Aarhus adiabatic oscillation package
• Seismic diagnostics for transport of angular momentum in stars 1. Rotational splittings from the PMS to the RGB
• Stellar Turbulent Convection: A Selfconsistent Model
• Weak magnetic fields in Ap/Bp stars: Evidence for a dipole field lower limit and a tentative interpretation of the magnetic dichotomy
• Dynamical Simulations of Magnetically Channeled Line-Driven Stellar Winds: II. The Effects of Field-Aligned Rotation
• Dynamical Simulations of Magnetically Channeled Line-Driven Stellar Winds: III. Angular Momentum Loss and Rotational Spindown
• Collapse of massive magnetized dense cores using radiation-magneto-hydrodynamics: early fragmentation inhibition
• CESAM: a free code for stellar evolution calculations
• Evolutionary state of magnetic chemically peculiar stars
• Searching for links between magnetic fields and stellar evolution. II. The evolution of magnetic fields as revealed by observations of Ap stars in open clusters and associations
• Asteroseismology and Interferometry
• Transport and mixing in the radiation zones of rotating stars II. Axisymmetric magnetic field
• The bottleneck of the CNO burning and the age of the Globular Clusters
• Ap stars with resolved magnetically split lines: Magnetic field determinations from Stokes $I$ and $V$ spectra
• Magnetic massive stars as progenitors of "heavy" stellar-mass black holes
• AIMS - A new tool for stellar parameter determinations using asteroseismic constraints
• A Volume Limited Survey of mCP Stars Within 100pc II: Rotational and Magnetic Properties
• The dependence of convective core overshooting on stellar mass: reality check, and additional evidence
• Helium abundance in a sample of cool stars: measurements from asteroseismology
• AmFm and lithium gap stars: Stellar evolution models with mass loss
• Envelope Convection, Surface Magnetism and Spots in A- and late B-type Stars
• Impacts of radiative accelerations on solar-like oscillating main-sequence stars
• Long-term evolution of a magnetic massive merger product
• An Investigation of the Rotational Properties of Magnetic Chemically Peculiar Stars
• The effects of surface fossil magnetic fields on massive star evolution: I. Magnetic field evolution, mass-loss quenching and magnetic braking
• The complementary roles of interferometry and asteroseismology in determining the mass of solar-type stars
• Possible pair-instability supernovae at solar metallicity from magnetic stellar progenitors
• Effects of Magnetic Fields on Photoionised Pillars and Globules
• Rotation and pulsation in Ap stars: first light results from TESS sectors 1 and 2
• The effects of surface fossil magnetic fields on massive star evolution: II. Implementation of magnetic braking in MESA and implications for the evolution of surface rotation in OB stars
• Asteroseismic modelling of solar-type stars: internal systematics from input physics and surface correction methods
• New Results on Standard Solar Models
• Radial Velocity Variations in Pulsating Ap Stars III. The Discovery of 16.21 min Oscillations in Beta CrB
• The Gaia-ESO survey: 3D NLTE abundances in the open cluster NGC 2420 suggest atomic diffusion and turbulent mixing at the origin of chemical abundance variations
• Improved pulsating models of magnetic Ap stars I: exploring different magnetic field configurations
• Sirius A: turbulence or mass loss?
• Discover of the "missing" mode in HR 1217 by the Whole Earth Telescope
• Model atmospheres of chemically peculiar stars: Self-consistent empirical stratified model of HD24712
• The fundamental parameters of the roAp star alpha Circini
• Testing excitation models of rapidly oscillating Ap stars with interferometry
• Asteroseismology and Exoplanets: Proceedings of the IVth Azores International Advanced School in Space Sciences
• Modelling element distributions in the atmospheres of magnetic Ap stars
• Discovery of the longest-period rapidly oscillating Ap star HD177765
• Asteroseismic analysis of the roAp star alpha Circini: 84 days of high-precision photometry from the WIRE satellite
• On mode conversion and wave reflection in magnetic Ap stars
• A self-consistent empirical model atmosphere, abundance and stratification analysis of the benchmark roAp star alpha Circini
• Asteroseismic modeling of gravity modes in slowly rotating A/F stars with radiative levitation
• Helium settling in F stars: constraining turbulent mixing using observed helium glitch signature
• A self consistent chemically stratified atmosphere model for the roAp star 10 Aquilae
• The radius and effective temperature of the binary Ap star beta CrB from CHARA/FLUOR and VLT/NACO observations
• Asteroseismic modelling of solar-type stars: A deeper look at the treatment of initial helium abundance
• The fundamental parameters of the roAp star $\gamma$ Equulei
• Three-dimensional abundance distributions in ApBp star atmospheres: non-axisymmetric magnetic geometry
• Fundamental parameters of bright Ap stars from wide-range energy distributions and advanced atmospheric models
• Fundamental parameters and evolutionary status of the magnetic chemically peculiar stars HD 188041 (V1291 Aquilae), HD 111133 (EP Virginis), and HD 204411. Spectroscopy versus interferometry
• Chemical mixing in low mass stars: I. Rotation against atomic diffusion including radiative accelerations
• The fundamental parameters of the roAp star 10 Aql
• Stellar models with self-consistent Rosseland opacities
• Effect of a magnetic field on massive star winds I: mass-loss and velocity for a dipole field
• A theoretical tool for the study of radial velocities in the atmospheres of roAp stars
• Putting atomic diffusion theory of magnetic ApBp stars to the test: evaluation of the predictions of time-dependent diffusion models
• Asteroseismic Stellar Modelling with AIMS
• New BRITE-Constellation observations of the roAp star Alpha Circini
• The search for roAp stars: null results and new candidates from Stroemgren-Crawford photometry

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• The effects of surface fossil magnetic fields on massive star evolution: IV. Grids of models at Solar, LMC, and SMC metallicities
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• Linking the primordial composition of planet building disks to the present-day composition of rocky exoplanets
• Ultraviolet Spectropolarimetry With Polstar: Using Polstar to test Magnetospheric Mass-loss Quenching
• MAISTEP -- a new grid-based machine learning tool for inferring stellar parameters I. Ages of giant-planet host stars
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