Asteroseismology of Cephei stars: The stellar inferences tested in hare and hound exercises
arXiv:2112.04064 · doi:10.1051/0004-6361/202142483
Abstract
The Cephei pulsators are massive main-sequence stars, presenting low radial-order modes. These modes probe in particular the chemical gradient at the edge of the convective core. They hence give constraints on macroscopic processes, such as hydrodynamic or magnetic instabilities. Yet, it is not clear to what extent the seismic inferences depend on the physics employed for the stellar modelling or on the observational dataset. We investigate the observational constraints which are necessary to provide accurate constraints on the mixing processes in Cephei stars. We explore the importance of the identification of the angular degree of modes. Depending on the quality of the seismic dataset and the classical constraints, we estimate the precision achievable with asteroseismology. We propose a method extending the forward approach classically used to model Cephei stars The probability distributions of the asteroseismic-derived stellar parameters are obtained. With these distributions, we provide a systemic way to estimate the errors of the modelling. A particular effort is made to also include the theoretical uncertainties of the models. We then estimate the accuracy and precision of asteroseismology for Cephei stars in a series of hare and hound exercises. The exercises show that a set of four to five oscillation frequencies with an identified angular degree already leads to accurate inferences on the stellar parameters. Without the identification of the modes, the addition of other classical observational constraints allow to succeed the seismic modelling. When the micro-physics of the star and stellar models used for the modelling differ, the constraints derived on the internal structure remain valid if expressed in terms of acoustic variables. The characterisation of the mixing processes at the boundary of the convective core remain model-dependent.
17 pages, 14 figures, accepted for publication in A&A
References in corpus (26)
- Present-day cosmic abundances. A comprehensive study of nearby early B-type stars and implications for stellar and Galactic evolution and interstellar dust models
- Probing the properties of convective cores through g modes: high-order g modes in SPB and gamma Doradus stars
- CLES, Code Liegeois d'Evolution Stellaire
- A cosmic abundance standard: chemical homogeneity of the solar neighbourhood and the ISM dust-phase composition
- Internal mixing of rotating stars inferred from dipole gravity modes
- The Liege Oscillation Code
- Abundance analysis of prime B-type targets for asteroseismology I. Nitrogen excess in slowly-rotating beta Cephei stars
- Variability of OB stars from TESS southern Sectors 1-13 and high-resolution IACOB and OWN spectroscopy
- The two hybrid B-type pulsators: Nu Eridani and 12 Lacertae
- The dependence of convective core overshooting on stellar mass: semi-empirical determination using the diffusive approach with two different element mixtures
- On the Chemical Mixing Induced by Internal Gravity Waves (IGW)
- Diverse Variability of O and B Stars Revealed from 2-minute Cadence Light Curves in Sectors 1 and 2 of the TESS Mission: Selection of an Asteroseismic Sample
- Demonstration of stellar intensity interferometry with the four VERITAS telescopes
- Probing the temperature gradient in the core boundary layer of stars with gravito-inertial modes: the case of KIC7760680
- delta Ceti is not monoperiodic: seismic modeling of a beta Cephei star from MOST spacebased photometry
- Convective core entrainment in 1D main sequence stellar models
- Interpretation of the BRITE oscillation data of the hybrid pulsator Eridani: a call for the modification of stellar opacities
- Variability of newly identified B-type stars observed by Kepler
- Convective core sizes in rotating massive stars: I. Constraints from solar metallicity OB field stars
- Pulsation spectrum of Delta Sct stars: the binary HD 50870 as seen with CoRoT and HARPS
- Combining BRITE and ground-based photometry for the Beta Cephei star Nu Eridani: impact on photometric pulsation mode identification and detection of several g modes
- Seismic modelling of early B-type pulsators observed by BRITE: I. Ophiuchi
- The Cep/SPB star 12 Lacertae: extended mode identification and complex seismic modelling
- 12 Bootis: a test bed for extra-mixing processes in stars
- Ensemble asteroseismology of pulsating B-type stars in NGC 6910
- Gravity modes and mixed modes as probes of stellar cores in main-sequence stars: from solar-like to beta Cep stars