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The influence of rotation on the asteroseismic fingerprint of slowly pulsating B (and Be) stars in the Kepler field
Peter Papics (Institute of Astronomy, KU Leuven (Belgium)), Andrew Tkachenko (Institute of Astronomy, KU Leuven (Belgium)), Conny Aerts (Institute of Astronomy, KU Leuven (Belgium))
Slowly pulsating B (SPB) stars are main sequence stars with a mass between 2.5 and 8 Solar mass that show non-radial heat-driven gravity-mode oscillations (see, e.g., Aerts et al. 2010, Chapter 2). Although it has been a quarter century since their discovery by Waelkens (1991), the first actual seismic modelling based on the high-order g-modes was only achieved recently for KIC 10526294 by Pápics et al. (2014). Even though these objects are not massive stars according to the classical definition, they share the same internal structure by having a convective core and a radiative envelope. This means that SPB stars are ideal asteroseismic probes of ill-understood internal mixing processes that have a significant influence on the lifetime of the metal factories of the Universe, such as core overshooting, diffusive mixing, or internal differential rotation. Therefore these stars hold the key to the precise calibration of stellar structure and evolution models of massive stars. We present five new SPB stars in the Kepler field that show unambiguous long series of gravity modes of the same degree l with consecutive radial order n. In comparison with similar stars that have been presented until now (KIC 10526294 by Pápics et al. 2014, Moravveji et al. 2015, and Triana et al. 2015; KIC 7760680 by Pápics et al. 2015), the rotation rates of these SPBs are clearly faster, with vsini values up to 240 km/s. Moreover, the fastest rotator shows weak Be signatures both in photometry and in spectroscopy. In-depth modelling of these stars will provide significant input (in terms of rotation and mixing properties) to a new generation of stellar structure models of massive stars, while some interesting conclusions can already be drawn from the shape of the detected period spacing patterns combined with fundamental parameters from high-resolution spectroscopy.