HD 165246: an early-type binary with a low mass ratio

Mayer, P.; Harmanec, P.; Pavlovski, K.

doi:10.1051/0004-6361/201220388

Cited by 21 publications

(51 citation statements)

References 35 publications

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“…This is in agreement with results on a sample of massive DEBs (Pavlovski & Hensberge 2005;Pavlovski & Southworth 2009Pavlovski et al , 2011Mayer et al 2013;Tkachenko et al 2014, with typical v rot sin i 100 km s −1 ), which also show no signs of mixing with CN-cycled matter. Mixing signatures are found in the remaining 1/3 of our sample stars.…”

Section: Evolutionary Status Of the Sample Starssupporting

confidence: 91%

“…The most accurate and precise fundamental parameters for massive stars available at present can be found in the compilation by Torres et al (2010, henceforth abbreviated TAG10), mainly for the most common among them, the early B-type stars of spectral types B0 to B3. Data on abundances of individual chemical elements in massive DEBs are scarce, though ongoing projects promise to alleviate the situation (Pavlovski & Hensberge 2005;Pavlovski & Southworth 2009Pavlovski et al , 2011Mayer et al 2013;Tkachenko et al 2014). …”

Section: Introductionmentioning

confidence: 99%

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Fundamental properties of nearby single early B-type stars

Nieva

Przybilla

2014

A&A

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Aims. Fundamental parameters of a sample of 26 apparently slowly-rotating single early B-type stars in OB associations and in the field within a distance of 400 pc from the Sun are presented and compared to high-precision data from detached eclipsing binaries (DEBs). Together with surface abundances for light elements the data are used to discuss the evolutionary status of the stars in context of the most recent Geneva grid of models for core hydrogen-burning stars in the mass-range ∼6 to 18 M at metallicity Z = 0.014. Methods. The fundamental parameters are derived on the basis of accurate and precise atmospheric parameters determined earlier by us from non-LTE analyses of high-quality spectra of the sample stars, utilising the new Geneva stellar evolution models. Results. Evolutionary masses plus radii and luminosities are determined to better than typically 5%, 10%, and 20% uncertainty, respectively, facilitating the mass−radius and mass−luminosity relationships to be recovered for single core hydrogen-burning objects with a similar precision as derived from DEBs. Good agreement between evolutionary and spectroscopic masses is found. Absolute visual and bolometric magnitudes are derived to typically ∼0.15−0.20 mag uncertainty. Metallicities are constrained to better than 15−20% uncertainty and tight constraints on evolutionary ages of the stars are provided. Overall, the spectroscopic distances and ages of individual sample stars agree with independently derived values for the host OB associations. Signatures of mixing with CN-cycled material are found in 1/3 of the sample stars. Typically, these are consistent with the amount predicted by the new Geneva models with rotation. The presence of magnetic fields appears to augment the mixing efficiency. In addition, a few objects are possibly the product of binary evolution. In particular, the unusual characteristics of τ Sco point to a blue straggler nature, due to a binary merger. Conclusions. The accuracy and precision achieved in the determination of fundamental stellar parameters from the quantitative spectroscopy of single early B-type stars comes close (within a factor 2-4) to data derived from DEBs. While our fundamental parameters are in good agreement with those derived from DEBs as a function of spectral type, significant systematic differences with data from the astrophysical reference literature are found. Masses are ∼10−20% and radii ∼25% lower then the recommended values for luminosity class V, resulting in the stars being systematically fainter than assumed usually, by ∼0.5 mag in absolute visual and bolometric magnitude. Our sample of giants is too small to derive firm conclusions, but similar trends as for the dwarfs are indicated.

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Section: Evolutionary Status Of the Sample Starssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Fundamental properties of nearby single early B-type stars

Nieva

Przybilla

2014

A&A

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“…There is no need for template spectra like in the cross-correlation method. This is highly beneficial in the case of barely visible components' spectrum, like in our case (see Mayer et al 2013;Torres et al 2014;Kolbas et al 2015, for other examples). With the method of spd the spectra of the faint dwarf companions were successfully reconstructed with the fractional light in the visual spectral region at the extreme values of barely ∼ 1 − 2 per cent.…”

Section: Parametermentioning

confidence: 61%

Oscillating red giants in eclipsing binary systems: empirical reference value for asteroseismic scaling relation

Themeßl

Hekker

Southworth

et al. 2018

Monthly Notices of the Royal Astronomical Society

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The internal structures and properties of oscillating red-giant stars can be accurately inferred through their global oscillation modes (asteroseismology). Based on 1460 days of Kepler observations we perform a thorough asteroseismic study to probe the stellar parameters and evolutionary stages of three red giants in eclipsing binary systems. We present the first detailed analysis of individual oscillation modes of the red-giant components of KIC 8410637, KIC 5640750 and KIC 9540226. We obtain estimates of their asteroseismic masses, radii, mean densities and logarithmic surface gravities by using the asteroseismic scaling relations as well as grid-based modelling. As these red giants are in double-lined eclipsing binaries, it is possible to derive their independent dynamical masses and radii from the orbital solution and compare it with the seismically inferred values. For KIC 5640750 we compute the first spectroscopic orbit based on both components of this system. We use high-resolution spectroscopic data and light curves of the three systems to determine up-to-date values of the dynamical stellar parameters. With our comprehensive set of stellar parameters we explore consistencies between binary analysis and asteroseismic methods, and test the reliability of the well-known scaling relations. For the three red giants under study, we find agreement between dynamical and asteroseismic stellar parameters in cases where the asteroseismic methods account for metallicity, temperature and mass dependence as well as surface effects. We are able to attain agreement from the scaling laws in all three systems if we use ∆ν ref,emp = 130.8 ± 0.9 µHz instead of the usual solar reference value.

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“…In the course of ourlong-term project to analyze early-type binaries and multiple systems, we mainly used FEROS archive data to identify hitherto unknown binaries among O stars and to obtain their fundamental parameters. An example of an already published study is the paper on HD 165246 (Mayer et al 2013).…”

Section: Introductionmentioning

confidence: 99%

New and revised parameters for several southern OB binaries

Mayer

Drechsel

Irrgang

2014

A&A

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Using ESO FEROS archive spectra of several southern OB-type binaries, we derived periods for three SB2 spectroscopic binaries, HD 97166, HD 115455, and HD 123590, and two SB1 systems, HD 130298 and HD 163892. It was also possible to use new FEROS spectra to improve the parameters of the known binaries, KX Vel and HD 167263. For KX Vel, we determined a dynamic mass of the primary of 16.8 M , while the evolutionary model suggests a higher value of 20.2 M . We derived an improved period for HD 167263, and in its spectra, we recognized contributions of both of its interferometric components.

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HD 165246: an early-type binary with a low mass ratio

Cited by 21 publications

References 35 publications

Fundamental properties of nearby single early B-type stars

Fundamental properties of nearby single early B-type stars

Oscillating red giants in eclipsing binary systems: empirical reference value for asteroseismic scaling relation

New and revised parameters for several southern OB binaries

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