The Dependence of Convective Core Overshooting on Stellar Mass: A Semi-empirical Determination Using the Diffusive Approach with Two Different Element Mixtures

Claret, A.; Torres, Guillermo

doi:10.3847/1538-4357/aa8770

Cited by 96 publications

(98 citation statements)

References 42 publications

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“…The fact that we do not reach the same mass of the convective core in the case of the α ov parameter suggests a somewhat larger conversion factor between the parametrizations, when interpreted in terms of efficiency of the mixing as to increasing the mass of the convective core. This is fully consistent with Claret & Torres (2017), who found the scaling α ov / f ov = 11.36 ± 0.22 based on their study of 56 individual stellar components of binary systems, while earlier studies by Moravveji et al (2016) and Valle et al (2017) suggested α ov / f ov ≈13 and 12, respectively.…”

Section: Step-like Cbm With Instantaneous Mixingsupporting

confidence: 90%

The mass discrepancy in intermediate- and high-mass eclipsing binaries: The need for higher convective core masses

Tkachenko

Pavlovski

Johnston

et al. 2020

A&A

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Context. Eclipsing, spectroscopic double-lined binary star systems (SB2) are excellent laboratories for calibrating theories of stellar interior structure and evolution. Their precise and accurate masses and radii measured from binary dynamics offer model-independent constraints and challenge current theories of stellar evolution. Aims. We aim to investigate the mass discrepancy in binary stars. This is the significant difference between stellar components' masses measured from binary dynamics and those inferred from models of stellar evolution via positions of the components in the T eff -log g Kiel diagram. We study the effect of near-core mixing on the mass of the convective core of the stars and interpret the results in the context of the mass discrepancy. Methods. We fit stellar isochrones computed from a grid of mesa stellar evolution models to a homogeneous sample of eleven highmass binary systems. Two scenarios are considered, where individual stellar components of a binary system are treated independent of each other and where they are forced to have the same age and initial chemical composition. We also study the effect of the microturbulent velocity and turbulent pressure on the atmosphere model structure and stellar spectral lines, and its link with the mass discrepancy.Results. We find that the mass discrepancy is present in our sample and that it is anti-correlated with the surface gravity of the star. No correlations are found with other fundamental and atmospheric parameters, including the stellar mass. The mass discrepancy can be partially accounted for by increasing the amount of near-core mixing in stellar evolution models. We also find that ignoring the microturbulent velocity and turbulent pressure in stellar atmosphere models of hot evolved stars results in overestimation of their effective temperature by up to 8%. Together with enhanced near-core mixing, this can almost entirely account for the ∼30% mass discrepancy found for the evolved primary component of V380 Cyg. Conclusions. We find a strong link between the mass discrepancy and the convective core mass. The mass discrepancy can be solved by considering the combined effect of extra near-core boundary mixing and consistent treatment in the spectrum analysis of hot evolved stars. Our binary modelling results in convective core masses between 17 and 35% of the stellar mass, in excellent agreement with results from gravity-mode asteroseismology of single stars. This implies larger helium core masses near the end of the main sequence than anticipated so far.

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Section: Step-like Cbm With Instantaneous Mixingsupporting

confidence: 90%

The mass discrepancy in intermediate- and high-mass eclipsing binaries: The need for higher convective core masses

Tkachenko

Pavlovski

Johnston

et al. 2020

A&A

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“…They used an alternate prescription of the core overshooting with a diffusion coefficient D ov = D 0 exp (−2z/H ν ), where z is the distance from the edge of the convective zone, D 0 the coefficient at z = 0, and H ν is defined with the overshooting parameter f ov such that H ν = f ov H p . MIST models adopted a fixed value f ov = 0.016 for all stellar masses, which would be approximatively converted to α ov ∼ 0.18 (Claret & Torres 2017).…”

Section: Evolutionary Statementioning

confidence: 99%

The Araucaria project: High-precision orbital parallax and masses of eclipsing binaries from infrared interferometry

Gallenne

Pietrzyński

Graczyk

et al. 2019

A&A

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Context. The precise determinations of stellar mass at 1 % provide important constraints on stellar evolution models. Accurate parallax measurements can also serve as independent benchmarks for the next Gaia data release. Aims. We aim at measuring the masses and distance of binary systems with a precision level better than 1 % using a fully geometrical and empirical method. Methods. We obtained the first interferometric observations for the eclipsing systems AI Phe, AL Dor, KW Hya, NN Del, ψ Cen and V4090 Sgr with the VLTI/PIONIER combiner, which we combined with radial velocity measurements to derive their threedimensional orbit, masses, and distance. Results. We determined very precise stellar masses for all systems, ranging from 0.04 % to 3.3 % precision level. We combined these measurements with stellar effective temperature and linear radius to fit stellar isochrones models and determined the age of the systems. We also derived the distance to the systems with a precision level as high as 0.4 %.Conclusions. The comparison of theoretical models with stellar parameters shows that stellar models are still deficient in simultaneously fitting the stellar parameters (T eff , R and M) with such level of precision on individual masses. This stresses the importance of precisely measuring the stellar parameters to better calibrate stellar evolution models. The precision of our model-independent orbital parallaxes varies from 24µas as to 70µas and they provide a unique opportunity to check on the future Gaia measurements for possible systematic errors.

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“…The last DEB systems compared to our models are four objects from the Claret & Torres (2017) Finally, we compare the mass-luminosity relationship predicted by our low-mass models in the V and K bands, with the data presented by Delfosse et al (2000), based mainly on visual and interferometric pairs. We display in Figure 21 First of all, as also noted by Delfosse et al (2000), the V-band data show a large dispersion at fixed M, with models matching a sort of upper envelope of the data.…”

Section: Binariesmentioning

confidence: 99%

The Updated BaSTI Stellar Evolution Models and Isochrones. I. Solar-scaled Calculations

Hidalgo

Pietrinferni

Cassisi

et al. 2018

ApJ

296

251

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The Updated BaSTI Stellar Evolution Models and Isochrones Hidalgo, S. L.; Pietrinferni, A.; Cassisi, S.; Salaris, M.; Mucciarelli, A.; Savino, A.; Aparicio, A.; Aguirre, V. Silva; Verma, K. Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. , with helium to metal enrichment ratio dY/dZ=1.31. The isochrones cover an age range between 20 Myr and 14.5 Gyr, consistently take into account the pre-main-sequence phase, and have been translated to a large number of popular photometric systems. Asteroseismic properties of the theoretical models have also been calculated. We compare our isochrones with results from independent databases and with several sets of observations to test the accuracy of the calculations. All stellar evolution tracks, asteroseismic properties, and isochrones are made available through a dedicated web site.

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The Dependence of Convective Core Overshooting on Stellar Mass: A Semi-empirical Determination Using the Diffusive Approach with Two Different Element Mixtures

Cited by 96 publications

References 42 publications

The mass discrepancy in intermediate- and high-mass eclipsing binaries: The need for higher convective core masses

The mass discrepancy in intermediate- and high-mass eclipsing binaries: The need for higher convective core masses

The Araucaria project: High-precision orbital parallax and masses of eclipsing binaries from infrared interferometry

The Updated BaSTI Stellar Evolution Models and Isochrones. I. Solar-scaled Calculations

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