Physical properties of seven binary and higher-order multiple OB systems

Mayer, P.; Harmanec, P.; Chini, R.; Nasseri, A.; Nemravová, J.; Drechsel, H.; Catalan-Hurtado, Rodrigo; Barlow, B. N.; Frémat, Y.; Kotková, L.

doi:10.1051/0004-6361/201628852

Cited by 16 publications

(20 citation statements)

References 68 publications

(118 reference statements)

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“…The one-sector TESS data set shows stochastic low frequency variability, and the dominant frequency satisfies our significance criterion, ν = 0.4753(7) d −1 . This approximately corresponds to the short-period found by Mayer et al (2017) but from the light curve it is unclear whether this dominant periodicity is due to binarity. HD 76556 (O6 IV(n)((f))p, Sota et al 2014) is a long-period double-lined spectroscopic binary (Chini et al 2012).…”

Section: Appendix B5: Binariessupporting

confidence: 60%

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Variability of OB stars from TESS southern Sectors 1–13 and high-resolution IACOB and OWN spectroscopy

Burssens

Simón‐Díaz

Bowman

et al. 2020

A&A

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Context. The lack of high-precision long-term continuous photometric data for large samples of stars has impeded the large-scale exploration of pulsational variability in the OB star regime. As a result, the candidates for in-depth asteroseismic modelling have remained limited to a few dozen dwarfs. The TESS nominal space mission has surveyed the southern sky, including parts of the galactic plane, yielding continuous data across at least 27 d for hundreds of OB stars. Aims. We aim to couple TESS data in the southern sky with ground-based spectroscopy to study the variability in two dimensions, mass and evolution. We focus mainly on the presence of coherent pulsation modes that may or may not be present in the predicted theoretical instability domains and unravel all frequency behaviour in the amplitude spectra of the TESS data. Methods. We compose a sample of 98 OB-type stars observed by TESS in Sectors 1–13 and with available multi-epoch, high-resolution spectroscopy gathered by the IACOB and OWN surveys. We present the short-cadence 2 min light curves of dozens of OB-type stars, which have one or more spectra in the IACOB or OWN database. Based on these light curves and their Lomb–Scargle periodograms, we performed variability classification and frequency analysis. We placed the stars in the spectroscopic Hertzsprung–Russell diagram to interpret the variability in an evolutionary context. Results. We deduce the diverse origins of the mmag-level variability found in all of the 98 OB stars in the TESS data. We find among the sample several new variable stars, including three hybrid pulsators, three eclipsing binaries, high frequency modes in a Be star, and potential heat-driven pulsations in two Oe stars. Conclusions. We identify stars for which future asteroseismic modelling is possible, provided mode identification is achieved. By comparing the position of the variables to theoretical instability strips, we discuss the current shortcomings in non-adiabatic pulsation theory and the distribution of pulsators in the upper Hertzsprung–Russell diagram.

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Section: Appendix B5: Binariessupporting

confidence: 60%

“…HD 123056 (O9.5 IV(n), Sota et al 2014) is a multiple system with three confirmed components, a high-mass O star orbiting in long period (∼ 1314 d) around a short-period inner pair (< 2 d) of early B stars (Mayer et al 2017). It is found to be SB1 in the IACOB/OWN spectroscopy.…”

Section: Appendix B5: Binariesmentioning

confidence: 99%

Variability of OB stars from TESS southern Sectors 1–13 and high-resolution IACOB and OWN spectroscopy

Burssens

Simón‐Díaz

Bowman

et al. 2020

A&A

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“…Until very recently, observations of high-mass binaries have commonly revealed systems with nearly equal masses (e.g. Pinsonneault & Stanek 2006;Mayer et al 2017).…”

Section: High-mass Binaries (Primary Star Mass > 5 M⊙)mentioning

confidence: 99%

On the initial binary population for star cluster simulations

Belloni

Askar

Giersz

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Colour-magnitude diagrams (CMDs) are powerful tools that might be used to infer stellar properties in globular clusters (GCs), for example, the binary fraction and their mass ratio (q) distribution. In the past few years, observations have revealed that q distributions of GC mainsequence (MS) binaries are generally flat, and a distribution characterized by a strong increase towards q ≈ 1 is not typical in GCs. In numerical simulations of GC evolution with the initial binary population (IBP) described by Kroupa, synthetic CMD colour distributions exhibit a peak associated with binaries that have q ≈ 1. While the Kroupa IBP reproduces binary properties in star-forming regions, clusters and the Galactic field, the peak in the q distribution towards q ≈ 1 observed for GC simulations is not consistent with distributions derived from observations. The objective of this paper is to refine and further improve the physical formulation of pre-main-sequence eigenevolution proposed by Kroupa in order to achieve CMD colour distributions of simulated GC models similar to those observed in real GCs, and to get a similarly good agreement with binary properties for late-type binaries in the Galactic field. We present in this paper a modified Kroupa IBP, in which early-type stars follow observational distributions, and late-type stars are generated according to slightly modified pre-main-sequence eigenevolution prescriptions. Our modifications not only lead to a qualitatively good agreement with respect to long-term observations of late-type binaries in the Galactic field, but also resolve the above-mentioned problem related to binary distributions in GC models.

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“…We searched for low-mass companions in OB star binaries (Moritani et al 2018). The analysis of the 10 target stars is still ongoing, among which HD 164438 is reported to have an intermediate-mass star with the mass ratio of q = M 2 /M 1 = 0.1 -0.2 (Mayer et al 2017), where M 1 and M 2 is the initial mass of a primary and secondary, respectively. Although we have not yet established the population of binary systems in the solar vicinity, we can expect some fraction of stars that are metal-rich counterparts of the first-generation massive binaries.…”

Section: Discussionmentioning

confidence: 99%

First Star Survivors as Metal-Rich Halo Stars that Experienced Supernova Explosions in Binary Systems

Suda,

Saitoh,

Moritani

et al. 2021

Preprint

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The search for the first stars formed from metal-free gas in the universe is one of the key issues in astronomy because it relates to many fields, such as the formation of stars and galaxies, the evolution of the universe, and the origin of elements. It is not still clear if metal-free first stars can be found in the present universe. These first stars are thought to exist among extremely metal-poor stars in the halo of our Galaxy. Here we propose a new scenario for the formation 1

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Physical properties of seven binary and higher-order multiple OB systems

Cited by 16 publications

References 68 publications

Variability of OB stars from TESS southern Sectors 1–13 and high-resolution IACOB and OWN spectroscopy

Variability of OB stars from TESS southern Sectors 1–13 and high-resolution IACOB and OWN spectroscopy

On the initial binary population for star cluster simulations

First Star Survivors as Metal-Rich Halo Stars that Experienced Supernova Explosions in Binary Systems

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