Absolute dimensions of eclipsing binaries

Clausen, J. V.; Frandsen, S.; Bruntt, H.; Olsen, E. H.; Helt, B. E.; Gregersen, K.; Juncher, D.; Krogstrup, Peter

doi:10.1051/0004-6361/201014266

Cited by 28 publications

(50 citation statements)

References 62 publications

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“…Claret 2007;Lacy et al 2008;Clausen et al 2010). Although our results do not directly allow estimation of the errors in the recovered best convective core-overshooting parameter that is consistent with the observations, we found that the bias induced by a mild convective core overshooting scenario on age estimate is about one-half of the 1σ expected error in age estimate.…”

Section: Convective Core Overshootingcontrasting

confidence: 72%

“…This sometimes leads to introducing and/or calibrating some physical processes in evolutionary codes, such as convective core overshooting, or to varying the external convection efficiency through the mixing-length parameter (see e.g. Andersen 1991;Pols et al 1997;Ribas et al 2000;Torres et al 2006Torres et al , 2010Torres et al , 2014Morales et al 2009;Clausen et al 2009Clausen et al , 2010, and references therein).…”

Section: Introductionmentioning

confidence: 99%

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Grid-based estimates of stellar ages in binary systems

Valle

Dell’Omodarme

Moroni

et al. 2015

A&A

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Aims. We investigate the performance of grid-based techniques in estimating the age of stars in detached eclipsing binary systems. We evaluate the precision of the estimates due to the uncertainty in the observational constraints -masses, radii, effective temperatures, and [Fe/H] -and the systematic bias caused by the uncertainty in convective core overshooting, element diffusion, mixing-length value, and initial helium content. Methods. We adopted the SCEPtER grid, which includes stars with mass in the range [0.8; 1.6] M and evolutionary stages from the zero-age main sequence to the central hydrogen depletion. Age estimates have been obtained by a generalisation of the maximum likelihood technique described in our previous work. Results. We showed that the typical 1σ random error in age estimates -due only to the uncertainty affecting the observational constraints -is about ±7%, which is nearly independent of the masses of the two stars. However, such an error strongly depends on the evolutionary phase and becomes larger and asymmetric for stars near the zero-age main sequence where it ranges from about +90% to −25%. The systematic bias due to the including convective core overshooting -for mild and strong overshooting scenariosis about 50% and 120% of the error due to observational uncertainties. A variation of ±1 in the helium-to-metal enrichment ratio ΔY/ΔZ accounts for about ±150% of the random error. The neglect of microscopic diffusion accounts for a bias of about 60% of the error due to observational uncertainties. We also introduced a statistical test of the expected difference in the recovered age of two coeval stars in a binary system. We find that random fluctuations within the current observational uncertainties can lead genuine coeval binary components to appear to be non-coeval with a difference in age as high as 60%.

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Section: Convective Core Overshootingcontrasting

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Grid-based estimates of stellar ages in binary systems

Valle

Dell’Omodarme

Moroni

et al. 2015

A&A

View full text Add to dashboard Cite

show abstract

“…This or a similar test is often applied to binaries in order to test stellar evolution and investigate convective core overshooting (see e.g. Andersen 1991;Schroder et al 1997;Pols et al 1997;Clausen et al 2010;Torres et al 2010Torres et al , 2014, and references therein).…”

Section: Description Of Our Testmentioning

confidence: 99%

Bonnsai: a Bayesian tool for comparing stars with stellar evolution models

Schneider

Langer

Koter

et al. 2014

A&A

147

155

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Powerful telescopes equipped with multi-fibre or integral field spectrographs combined with detailed models of stellar atmospheres and automated fitting techniques allow for the analysis of large number of stars. These datasets contain a wealth of information that require new analysis techniques to bridge the gap between observations and stellar evolution models. To that end, we develop B (BONN Stellar Astrophysics Interface), a Bayesian statistical method, that is capable of comparing all available observables simultaneously to stellar models while taking observed uncertainties and prior knowledge such as initial mass functions and distributions of stellar rotational velocities into account. B can be used to (1) determine probability distributions of fundamental stellar parameters such as initial masses and stellar ages from complex datasets; (2) predict stellar parameters that were not yet observationally determined; and (3) test stellar models to further advance our understanding of stellar evolution. An important aspect of B is that it singles out stars that cannot be reproduced by stellar models through χ 2 hypothesis tests and posterior predictive checks. B can be used with any set of stellar models and currently supports massive main-sequence single star models of Milky Way and Large and Small Magellanic Cloud composition. We apply our new method to mock stars to demonstrate its functionality and capabilities. In a first application, we use B to test the stellar models of Brott et al. (2011, A&A, 530, A115) by comparing the stellar ages inferred for the primary and secondary stars of eclipsing Milky Way binaries of which the components range in mass between 4.5 and 28 M . Ages are determined from dynamical masses and radii that are known to better than 3%. We show that the stellar models must include rotation because stellar radii can be increased by several percent via centrifugal forces. We find that the average age difference between the primary and secondary stars of the binaries is 0.9 ± 2.3 Myr (95% CI), i.e. that the stellar models reproduce the Milky Way binaries well. The predicted effective temperatures are in agreement for observed effective temperatures for stars cooler than 25 000 K. In hotter stars, i.e. stars earlier than B1-2V and more massive than about 10 M , we find that the observed effective temperatures are on average hotter by 1.1 ± 0.3 kK (95% CI) and the bolometric luminosities are consequently larger by 0.06 ± 0.02 dex (95% CI) than predicted by the stellar models.

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“…Stellar models succeed in predicting the mass-radius relation to an accuracy of a few percent for main-sequence stars with M M M 5  < <   (e.g., Andersen 1991). Systematic discrepancies between model and observation in the mass-radius relation for a given age have been associated with the amount of convective core overshoot by Clausen et al (2010), but these are below 1%. Low-mass stars with M M  <  are the most common stars in the solar neighborhood, but only a very limited number of these are well-characterized (Torres 2013).…”

Section: Introductionmentioning

confidence: 99%

An M Dwarf Companion to an F-Type Star in a Young Main-Sequence Binary

Eigmüller¹,

Eislöffel²,

Csizmadia³

et al. 2016

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Only a few well characterized very low-mass M dwarfs are known today. Our understanding of M dwarfs is vital as these are the most common stars in our solar neighborhood. We aim to characterize the properties of a rare F+dM stellar system for a better understanding of the low-mass end of the Hertzsprung-Russel diagram. We used photometric light curves and radial velocity follow-up measurements to study the binary. Spectroscopic analysis was used in combination with isochrone fitting to characterize the primary star. The primary star is an early F-type main-sequence star with a mass of (1.493 ± 0.073) M e and a radius of (1.474 ± 0.040) R e . The companion is an M dwarf with a mass of (0.188 ± 0.014) M e and a radius of (0.234 ± 0.009) R e . The orbital period is (1.35121±0.00001) days. The secondary star is among the lowest-mass M dwarfs known to date. The binary has not reached a 1:1 spin-orbit synchronization. This indicates a young main-sequence binary with an age below ∼250 Myr. The mass-radius relation of both components are in agreement with this finding.

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Absolute dimensions of eclipsing binaries

Cited by 28 publications

References 62 publications

Grid-based estimates of stellar ages in binary systems

Grid-based estimates of stellar ages in binary systems

Bonnsai: a Bayesian tool for comparing stars with stellar evolution models

An M Dwarf Companion to an F-Type Star in a Young Main-Sequence Binary

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