Internal Gravity Waves in Massive Stars: Angular Momentum Transport

Rogers, T. M.; Lin, D. N. C.; McElwaine, J. N.; Lau, Herbert H. B.

doi:10.1088/0004-637x/772/1/21

Cited by 241 publications

(396 citation statements)

References 80 publications

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“…However, Be stars are very rapid rotators and stochastic excitation is enhanced in the presence of rapid rotation, through the Coriolis acceleration which modifies gravity waves. This has been demonstrated analytically by Mathis et al (2013) and observed in numerical simulations by Rogers et al (2013) …”

Section: Stochastic Excitation Of Pulsations In Be Starsmentioning

confidence: 55%

Making a Be star: the role of rotation and pulsations

Neiner¹,

Mathis²

2013

Proc. IAU

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Abstract. The Be phenomenon, i.e. the ejection of matter from Be stars into a circumstellar disk, has been a long lasting mystery. In the last few years, the CoRoT satellite brought clear evidence that Be outbursts are directly correlated to pulsations and rapid rotation. In particular the stochastic excitation of gravito-inertial modes, such as those detected by CoRoT in the hot Be star HD 51452, is enhanced thanks to rapid rotation. These waves increase the transport of angular momentum and help to bring the already rapid stellar rotation to its critical value at the surface, allowing the star to eject material. Below we summarize the recent observational and theoretical findings and describe the new picture of the Be phenomenon which arose from these results.

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Section: Stochastic Excitation Of Pulsations In Be Starsmentioning

confidence: 55%

Making a Be star: the role of rotation and pulsations

Neiner¹,

Mathis²

2013

Proc. IAU

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“…These IGWs are highly efficient at transporting angular momentum to the stellar surface (e.g., Rogers & Glatzmaier 2005;Rogers et al 2013). On the other hand, convection-driven IGWs are linked to the stochastic motion by the convective plumes escaping the convective core (e.g., Goldreich & Kumar 1990;Samadi et al 2010;Shiode et al 2013;Mathis et al 2014).…”

Section: The Pulsating Magnetic Hot Star Hd 43317mentioning

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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“…Meanwhile, a 1-σ detection of counter-rotation in a main-sequence B star (KIC 10526294, Triana et al 2015) appears to require even more elaborate angular momentum transport, but the observations are consistent with rigid rotation within 2 σ and the star's rotation period is also remarkably long at ∼ 188 d (Pápics et al 2014). Internal gravity waves could be responsible for these uniform or even counter-rotating profiles (Rogers et al 2013).…”

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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Internal Gravity Waves in Massive Stars: Angular Momentum Transport

Cited by 241 publications

References 80 publications

Making a Be star: the role of rotation and pulsations

Making a Be star: the role of rotation and pulsations

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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