Gravity-mode period spacings as seismic diagnostic for a sample of gamma Doradus stars from Kepler space photometry and high-resolution ground-based spectroscopy

Kepler's first view of O-star variability:K2data of five O stars in Campaign 0 as a proof of concept for O-star asteroseismology

“…The 1.2-m Mercator telescope is dedicated to the long-term monitoring of variable stars, including heat-driven pulsators (e.g., De Cat et al 2007;Cuypers et al 2009) and evolved low-mass stars (e.g., Van Winckel et al 2009). A large fraction of the telescope time in the recent years has been used for the spectroscopic monitoring of bright Kepler targets (e.g., Lehmann et al 2011;Tkachenko et al 2012;Beck et al 2014;Niemczura et al 2015;Van Reeth et al 2015).…”

“…The 1.2-m Mercator telescope is dedicated to the long-term monitoring of variable stars, including heat-driven pulsators (e.g., De Cat et al 2007;Cuypers et al 2009) and evolved low-mass stars (e.g., Van Winckel et al 2009). A large fraction of the telescope time in the recent years has been used for the spectroscopic monitoring of bright Kepler targets (e.g., Lehmann et al 2011;Tkachenko et al 2012;Beck et al 2014;Niemczura et al 2015;Van Reeth et al 2015). In view of its photometric behaviour and of recent theoretical predictions that more than 70% of all O-type stars occur in binaries (Sana et al 2012), we added EPIC 202060092 to the observing programme for measurements with the hermes spectrograph (Raskin et al 2011).…”

“…The latter are the compact remnants of low-mass stars that were very successfully studied from groundbased mmag-precision asteroseismology more than two decades ago (e.g., Córsico et al 2008, and references therein) but they were hardly monitored seismically from space due to their faintness and fast oscillations of tens of seconds (Østensen et al 2011;Bischoff-Kim & Østensen 2011;Hermes et al 2011). The heatdriven pressure and/or gravity modes detected in hundreds of intermediate-mass stars are much harder to analyse and interpret theoretically than the stochastically-excited solar-like pulsators, but major progress is also underway for such objects (Kurtz et al 2014;Saio et al 2015;Van Reeth et al 2015).…”