Thorough characterisation of the 16 Cygni system

Abstract

Context. Being part of the brightest solar-like stars, and close solar analogues, the 16 Cygni system is of great interest to the scientific community and may provide insight into the past and future evolution of our Sun. It has been observed thoroughly by the Kepler satellite, which provided us with data of an unprecedented quality. Aims. This paper is the first of a series aiming to extensively characterise the system. We test several choices of micro- and macro-physics to highlight their effects on optimal stellar parameters and provide realistic stellar parameter ranges. Methods. We used a recently developed method, WhoSGlAd, that takes the utmost advantage of the whole oscillation spectrum of solar-like stars by simultaneously adjusting the acoustic glitches and the smoothly varying trend. For each choice of input physics, we computed models which account, at best, for a set of seismic indicators that are representative of the stellar structure and are as uncorrelated as possible. The search for optimal models was carried out through a Levenberg-Marquardt minimisation. First, we found individual optimal models for both stars. We then selected the best candidates to fit both stars while imposing a common age and composition. Results. We computed realistic ranges of stellar parameters for individual stars. We also provide two models of the system regarded as a whole. We were not able to build binary models with the whole set of choices of input physics considered for individual stars as our constraints seem too stringent. We may need to include additional parameters to the optimal model search or invoke non-standard physical processes.

On the stellar core physics of the 16 Cyg binary system: constraining the central hydrogen abundance using asteroseismology

“…The top left panel of Figure 4 shows a comparison of the derived masses of 16 Cyg A and B from our grids with those estimated from White et al (2013), Bellinger et al (2016), andFarnir et al (2020). The masses of both 16 Cyg A and B inferred from all the grids agree within 1-2 uncertainties with literature findings.…”

“…angular diameter), sets a platform for constraining stellar interior physics and fundamental parameters to unprecedented levels (e.g. Metcalfe et al 2010Metcalfe et al , 2012Pinsonneault et al 2014;Valle et al 2015;Silva Aguirre et al 2017;Joyce & Chaboyer 2018;Campante et al 2019;Bellinger et al 2019; Jørgensen & Angelou ★ E-mail: nsamba@mpa-garching.mpg.de † E-mail: mcunha@astro.up.pt 2019; Ball et al 2020;Jiang et al 2020;Bowman 2020;Farnir et al 2020;Nsamba et al 2021;Deal et al 2021, among others). In addition, this information has been employed in the precise characterisation of exoplanetary systems (e.g.…”

Thorough characterisation of the 16 Cygni system. Part II. Seismic inversions of the internal structure

“…While the trend remains, its origin is not entirely clear and might even potentially be spurious. In this respect we consider the results of the evolutionary modelling of Farnir et al (2020) to be far more robust than the claimed accepted parameters of Buldgen et al (2016a) for the 16Cyg system.…”

“…A full re-analysis with various evolutionary models was provided by the extensive modelling work of Farnir et al (2020), hereafter Paper I. The authors carried out a detailed study of 16Cyg A&B using the WhoSGlAd oscillation spectrum modelling technique.…”

Multi-cavity gravito-acoustic modes in stars: A general analytical resonance condition

“…The exquisite store of seismic data collected by space-borne missions CoRoT and Kepler subsequently enabled similar studies in dozens of other distant main-sequence stars (e.g., Mazumdar et al 2012;Lebreton & Goupil 2012;Mazumdar et al 2014;Verma et al 2017;Farnir et al 2020b). All the seismic information extracted from acoustic glitches currently stand for one of the most important sources of constraints for stellar modeling (e.g., Verma & Silva Aguirre 2019;Farnir et al 2020a).…”