Asteroseismic Fingerprints of Rotation and Mixing in the Slowly Pulsating B8 v Star Kic 7760680

Pápics, P. I.; Tkachenko, A.; Aerts, C.; Reeth, T. Van; Smedt, K. De; Hillen, M.; Østensen, R. H.; Moravveji, E.

doi:10.1088/2041-8205/803/2/l25

Cited by 70 publications

(141 citation statements)

References 35 publications

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“…27. Main observed period spacing patterns of the five SPB stars studied in this paper along with those of KIC 10526294 and KIC 7760680 from Pápics et al (2014Pápics et al ( , 2015. The colours represent the projected rotation velocity of the star; slow rotators are plotted using dark symbols and fast rotators using bright symbols.…”

Section: Discussionmentioning

confidence: 97%

Signatures of internal rotation discovered in theKeplerdata of five slowly pulsating B stars

Pápics

Tkachenko

Reeth

et al. 2017

A&A

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Context. Massive stars are important building blocks of the Universe, and their stellar structure and evolution models are fundamental cornerstones of various fields in modern astrophysics. The precision of these models is strongly limited by our lack of understanding of various internal mixing processes that significantly influence the lifetime of these objects, such as core overshoot, chemical mixing, or the internal differential rotation. Aims. Our goal is to calibrate models by extending the sample of available seismic studies of slowly pulsating B (SPB) stars, providing input for theoretical modelling efforts that will deliver precise constraints on the parameters describing the internal mixing processes in these objects. Methods. We used spectral synthesis and disentangling techniques to derive fundamental parameters and to determine precise orbital parameters from high-resolution spectra. We employed custom masks to construct light curves from the virtually uninterrupted four year long Kepler pixel data and used standard time-series analysis tools to construct a set of significant frequencies for each target. These sets were first filtered from combination frequencies, and then screened for period spacing patterns. Results. We detect gravity mode period series of modes, of the same degree with consecutive radial order n, in four new and one revisited SPB star. These series (covering typically 10 to 40 radial orders) are clearly influenced by moderate to fast rotation and carry signatures of chemical mixing processes. Furthermore, they are predominantly prograde dipole series. Our spectroscopic analysis, in addition to placing each object inside the SPB instability strip and identifying KIC 4930889 as an SB2 binary, reveals that KIC 11971405 is a fast rotator that shows very weak Be signatures. Together with the observed photometric outbursts this illustrates that this Be star is a fast rotating SPB star. We hypothesise that the outbursts might be connected to its very densely compressed oscillation spectrum.

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Section: Discussionmentioning

confidence: 97%

Signatures of internal rotation discovered in theKeplerdata of five slowly pulsating B stars

Pápics

Tkachenko

Reeth

et al. 2017

A&A

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155

232

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“…In a future paper, the observed pulsation modes will be used to constrain the stellar structure through forward modeling (as done in, e.g., Degroote et al 2010;Pápics et al 2015;Van Reeth et al 2016;Moravveji et al 2016). At this stage, however, we can already employ several theoretical criteria to study whether or not the magnetic field at the stellar surface of HD 43317 is sufficiently strong to imply solid-body rotation.…”

Section: Implications For the Stellar Interiormentioning

confidence: 99%

Magnetic characterization of the SPB/β Cep hybrid pulsator HD 43317

Buysschaert

Neiner

Briquet

et al. 2017

A&A

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Large-scale magnetic fields at the surface of massive stars do not only influence the outer-most layers of the star, but also have consequences for the deep interior, only observationally accessible through asteroseismology. We performed a detailed characterization of the dipolar magnetic field at the surface of the B3.5V star HD 43317, a SPB/β Cep hybrid pulsator, by studying the rotationally modulated magnetic field of archival and new Narval spectropolarimetry. Additionally, we employed a grid-based approach to compare the Zeeman signatures with model profiles. By studying the rotational modulation of the He lines in both the Narval and HARPS spectroscopy caused by co-rotating surface abundance inhomogeneities, we updated the rotation period to 0.897673 ± 0.000004 d. The inclination angle between the rotation axis and the observer's line of sight remains ill-defined, because of the low level of variability in Stokes V and deformations in the intensity profiles by stellar pulsation modes. The obliquity angle between the rotation and magnetic axes is constrained to β ∈ [67, 90] • , and the strength of the dipolar magnetic field is of the order of 1 kG to 1.5 kG. This magnetic field at the stellar surface is sufficiently strong to warrant a uniformly rotating radiative envelope, causing less convective core overshooting, which should be visible in future forward seismic modeling.

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“…In the last few years, we have begun to observe with asteroseismology the internal radial rotation profiles of stars from hydrogen-burning main-sequence phases Pápics et al 2015;Saio et al 2015;Schmid et al 2015;Triana et al 2015), through to subgiant and red giant phases (Beck et al 2012;Mosser et al 2012;Deheuvels et al 2012Deheuvels et al , 2014Deheuvels et al , 2015, and even on to the late evolutionary stages of subdwarf B stars (Van Grootel et al 2009) and white dwarfs ).…”

Section: Introductionmentioning

confidence: 99%

Near-uniform internal rotation of the main-sequence γ Doradus pulsator KIC 7661054

Murphy

Fossati

Bedding

et al. 2016

Mon. Not. R. Astron. Soc.

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We used Kepler photometry to determine the internal rotation rate of KIC 7661054, a chemically normal γ Dor star on the main sequence at spectral type F2.5 V. The core rotation period of 27.25 ± 0.06 d is obtained from the rotational splittings of a series of dipole g modes. The surface rotation period is calculated from a spectroscopic projected rotation velocity and a stellar radius computed from models. Literature data, obtained without inclusion of macroturbulence as a line-broadening mechanism, imply that the surface rotates much more quickly than the core, while our detailed analysis suggests that the surface may rotate slightly more quickly than the core and that the rotation profile is uniform within the 1-σ uncertainties. We discuss the pitfalls associated with the determination of surface rotation rates of slow rotators from spectroscopy in the absence of asteroseismic constraints. A broad signal is observed at low frequency, which we show cannot be attributed to rotation, contrary to previous suggestions concerning the origin of such signals.

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Asteroseismic Fingerprints of Rotation and Mixing in the Slowly Pulsating B8 v Star Kic 7760680

Cited by 70 publications

References 35 publications

Signatures of internal rotation discovered in theKeplerdata of five slowly pulsating B stars

Signatures of internal rotation discovered in theKeplerdata of five slowly pulsating B stars

Magnetic characterization of the SPB/β Cep hybrid pulsator HD 43317

Near-uniform internal rotation of the main-sequence γ Doradus pulsator KIC 7661054

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