Probing stellar cores from inversions of frequency separation ratios

Bétrisey, J.; Buldgen, G.

doi:10.1051/0004-6361/202243640

A&A

2022

DOI: 10.1051/0004-6361/202243640

|View full text |Cite

Probing stellar cores from inversions of frequency separation ratios

J. Bétrisey

G. Buldgen

Abstract: Context. With the rapid development of asteroseismology thanks to space-based photometry missions such as CoRoT, Kepler, TESS, and in the future, PLATO, and the use of inversion techniques, quasi-model-independent constraints on the stellar properties can be extracted from a given stellar oscillation spectrum. In this context, inversions based on frequency separation ratios, which are less sensitive to surface effects, appear as a promising technique to constrain the properties of stellar convective cores. Aim… Show more

Help me understand this report

Search citation statements

Order By: Relevance

Paper Sections

Select...

Citation Types

Supporting

Mentioning

Contrasting

Year Published

2022

2024

Publication Types

Select...

Article4

Relationship

Self Cite0

Independent4

Authors

Journals

Cited by 4 publications

References 52 publications

(47 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

Asteroseismic modelling strategies in the PLATO era

Bétrisey¹,

Buldgen²,

Reese³

et al. 2023

A&A

View full text Add to dashboard Cite

Context. Asteroseismology experienced a breakthrough in the last two decades thanks to the so-called photometry revolution with space-based missions such as CoRoT, Kepler, and TESS. Because asteroseismic modelling will be part of the pipeline of the future PLATO mission, it is relevant to compare some of the current modelling strategies and discuss the limitations and remaining challenges for PLATO. In this first paper, we focused on modelling techniques treating directly the seismic information. Aims. We compared two modelling strategies by directly fitting the individual frequencies or by coupling a mean density inversion with a fit of the frequency separation ratios. Methods. We applied these two modelling approaches to six synthetic targets with a patched atmosphere, for which the observed frequencies were obtained with a non-adiabatic oscillation code. We then studied ten actual targets from the Kepler LEGACY sample. Results. As is well known, the fit of the individual frequencies is very sensitive to the surface effects and to the choice of the underlying prescription for semi-empirical surface effects. This significantly limits the accuracy and precision that can be achieved for the stellar parameters. The mass and radius tend to be overestimated, and the age therefore tends to be underestimated. In contrast, the second strategy, which is based on mean density inversions and on the ratios, efficiently damps the surface effects and allows us to obtain precise and accurate stellar parameters. The average statistical precision of our selection of targets from the LEGACY sample with this second strategy is 1.9% for the mass, 0.7% for the radius, and 4.1% for the age. This is well within the PLATO mission requirements. The addition of the inverted mean density to the constraints significantly improves the precision of the stellar parameters by 20%, 33%, and 16% on average for the stellar mass, radius, and age, respectively. Conclusions. The modelling strategy based on mean density inversions and frequencies separation ratios showed promising results for PLATO because it achieved a precision and accuracy on the stellar parameters that meet the PLATO mission requirements with ten Kepler LEGACY targets. The strategy also left some margin for other unaccounted systematics, such as the choice of the physical ingredients of the stellar models or the stellar activity.

show abstract

Asteroseismic modelling strategies in the PLATO era

Bétrisey¹,

Buldgen²,

Reese³

et al. 2023

A&A

View full text Add to dashboard Cite

show abstract

Asteroseismic modelling strategies in the PLATO era

Bétrisey,

Buldgen,

Reese

et al. 2024

A&A

View full text Add to dashboard Cite

In the framework of the PLATO mission, to be launched in late 2026, seismic inversion techniques will play a key role in determining the mission precision requirements in terms of stellar mass, radius, and age. It is therefore relevant to discuss the challenges of the automation of seismic inversions, which were originally developed for individual modelling. We tested the performance of our newly developed quality assessment procedure of seismic inversions, which was designed for pipeline implementation. We applied our assessment procedure to a testing set composed of 26 reference models. We divided our testing set into two categories: calibrator targets whose inversion behaviour is well known from the literature and targets for which we assessed the quality of the inversion manually. We then compared the results of our assessment procedure with our expectations as a human modeller for three types of inversions: the mean density inversion, the acoustic radius inversion, and the central entropy inversion. We find that our quality assessment procedure performs as well as a human modeller. The mean density inversion and the acoustic radius inversion are suited to large-scale applications, but not the central entropy inversion, at least in its current form. Our assessment procedure shows promising results for a pipeline implementation. It is based on the by-products of the inversion and therefore requires few numerical resources to quickly assess the quality of an inversion result.

show abstract

Imprint of the magnetic activity cycle on solar asteroseismic characterisation based on 26 years of GOLF and BiSON data

Bétrisey,

Farnir,

Breton

et al. 2024

A&A

View full text Add to dashboard Cite

Asteroseismic modelling will play a key role in future space-based missions, such as PLATO, CubeSpec, and Roman. Despite remarkable achievements, asteroseismology has revealed significant discrepancies between observations and theoretical predictions of the physics used in stellar models, which have the potential to bias stellar characterisation at the precision level demanded by PLATO. The current modelling strategies largely overlook magnetic activity, assuming that its effects are masked within the parametrisation of the so-called `surface effects'. Given the presence of activity cycles in multiple solar-like oscillators and activity variations in a significant fraction of Kepler observations of main-sequence stars, it is therefore relevant to investigate systematic errors in asteroseismic characterisations caused by our incomplete understanding of magnetic activity. Based on 26.5 years of GOLF and BiSON observations, we measured the impact of magnetic activity on the asteroseismic characterisation of the Sun as a star, a reference target for assessing the PLATO mission requirements. The GOLF and BiSON observations, which fully cover solar cycles 23 and 24, were divided into yearly overlapping snapshots, each delayed by a quarter of a year. For each snapshot, an advanced asteroseismic characterisation, similar to that to be adopted by the PLATO pipeline, was performed with standard prescriptions for the parametrisation of the surface effects. This allowed us to monitor the apparent temporal evolution of fundamental solar parameters such as mass, radius, and age. The correlation of these parameters with the 10.7 cm radio emission flux, a proxy of the solar activity cycle, was then measured. The effects of magnetic activity are partially absorbed into the parametrisation of the surface effects when suitable prescriptions are used, and they do not significantly affect the measured solar mass or radius. However, contrary to literature expectations, we find a significant imprint on the age determination, with variations of up to 6.5<!PCT!> between solar minima and maxima. This imprint persists across both BiSON and GOLF datasets. Considering that the Sun exhibits low levels of activity, our study highlights the looming challenge posed by magnetic activity for future photometry missions, and it prompts a potential reevaluation of the asteroseismic characterisation of the most active Kepler targets.

show abstract

scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.

Contact Info

hi@scite.ai

10624 S. Eastern Ave., Ste. A-614

Henderson, NV 89052, USA

Blog Terms and Conditions API Terms Privacy Policy Contact Cookie Preferences Do Not Sell or Share My Personal Information

Made with 💙 for researchers

Part of the Research Solutions Family.

Probing stellar cores from inversions of frequency separation ratios

Cited by 4 publications

References 52 publications

Asteroseismic modelling strategies in the PLATO era

Asteroseismic modelling strategies in the PLATO era

Asteroseismic modelling strategies in the PLATO era

Imprint of the magnetic activity cycle on solar asteroseismic characterisation based on 26 years of GOLF and BiSON data

Contact Info

Product

Resources

About