The gravity modes present in γ Doradus stars probe the deep stellar interiors and are thus of particular interest in asteroseismology. For the MUSICIAN programme at the University of Canterbury, we obtain extensive high-resolution echelle spectra of γ Dor stars from the Mt John University Observatory in New Zealand. We analyze these to obtain the pulsational frequencies and identify these with the multiple pulsational modes excited in the star. A summary of recent results from our spectroscopic mode-identification programme is given.

Our simultaneous analysis of ground-based photometric and high-resolution spectroscopic data of the δ Scuti star V376 Per revealed eight individual frequencies from 82 nights of two-color photometry and six frequencies from the line-profile variations using 769 stellar spectra. Additionally, we identified the corresponding pulsation modes and derived reliable estimates of the line profile and pulsation mode parameters.

This article reports some preliminary results on an analysis of line bisectors of metal absorption lines of RR Lyrae, the prototype of its class of pulsators. The extensive data set used for this study consists of a time series of spectra obtained at various pulsation phases as well as different Blazhko phases. This setup should allow a comparison of the atmospheric behaviour, especially of the function of radial velocity versus depth at differing Blazhko phases, but (almost) identical pulsation phase, making it possible to investigate whether the modulation causes a change in the atmospheric motion of RR Lyrae. While the nature of the Blazhko modulation has often been investigated photometrically and described as a change in the light curve, studies on time series of high resolution spectra are rare. We present for the first time work on line bisectors at different phases of RR Lyr.

Gravity waves, which propagate in radiation zones, can extract or deposit angular momentum by radiative and viscous damping. Another process, poorly explored in stellar physics, concerns their direct interaction with the differential rotation and the related turbulence. In this work, we thus study their corotation resonances, also called critical layers, that occur where the Doppler-shifted frequency of the wave approaches zero. First, we study the adiabatic and non-adiabatic propagation of gravity waves near critical layers. Next, we derive the induced transport of angular momentum. Finally, we use the dynamical stellar evolution code STAREVOL to apply the results to the case of a solar-like star. The results depend on the value of the Richardson number at the critical layer. In the first stable case, the wave is damped. In the other unstable and turbulent case, the wave can be reflected and transmitted by the critical layer with a coefficient larger than one: the critical layer acts as a secondary source of excitation for gravity waves. These new results can have a strong impact on our understanding of angular momentum transport processes in stellar interiors along stellar evolution where strong gradients of angular velocity can develop.

I present a personal view of Wojtek Dziembowski's scientific career, derived mainly from my direct interactions with Wojtek. Necessarily this presentation is biased towards the earlier days, partly because we interacted more then, and partly because the presentation after mine is by a local admirer who has been much more involved than I with Wojtek's later work.

Our current understanding and modeling of angular momentum transport in low-mass stars are briefly reviewed. Emphasis is set on single stars slightly younger that the Sun and on subgiants and red giants observed by the space missions CoRoT and Kepler.

We perform numerical simulations of the whole Sun using the 3D anelastic spherical harmonic (ASH) code. In such models, the radiative and convective zones are non-linearly coupled and in the radiative interior a wave-like pattern is observed. For the first time, we are thus able to model in 3D the excitation and propagation of internal gravity waves (IGWs) in a solar-like star's radiative zone. We compare the properties of our waves to theoretical predictions and results of oscillation calculations. The obtained good agreement allows us to validate the consistency of our approach and to study the characteristics of IGWs. We find that a wave's spectrum is excited up to radial order n=58. This spectrum evolves with depth and time; we show that the lifetime of the highest-frequency modes must be greater than 550 days. We also test the sensitivity of waves to rotation and are able to retrieve the rotation rate to within 5% error by measuring the frequency splitting.

IAU Commission 6 “Astronomical Telegrams” had a single business meeting during the Beijing General Assembly of the IAU. It took place on Friday, August 24, 2012. The meeting was attended by five C6 members (N. N. Samus; D. W. E. Green; S. Nakano; J. Ticha; and H. Yamaoka). Also present was Prof. F. Genova as a representative of the IAU Division B. She told the audience about the current restructuring of IAU Commissions and Divisions and consequences for the future of C6.

Spectropolarimetric observations combined with tomographic imaging techniques have revealed that all pre-main sequence (PMS) stars host multipolar magnetic fields, ranging from strong and globally axisymmetric with ≳kilo-Gauss dipole components, to complex and non-axisymmetric with weak dipole components (≲0.1 kG). Many host dominantly octupolar large-scale fields. We argue that the large-scale magnetic properties of a PMS star are related to its location in the Hertzsprung-Russell diagram. This conference paper is a synopsis of Gregory et al. (2012), updated to include the latest results from magnetic mapping studies of PMS stars.

The Kepler space telescope has proven to be a gold mine for the study of variable stars. Unfortunately, Kepler only returns a handful of pixels surrounding each star on the target list, which omits a large number of stars in the Kepler field. For the open clusters NGC 6791 and NGC 6819, Kepler also reads out larger superstamps which contain complete images of the central region of each cluster. These cluster images can potentially be used to study additional stars in the open clusters. We present preliminary results from using traditional photometric techniques to identify and analyze additional variable stars from these images.

We present the new, second spectroscopic telescope of Poznań Astronomical Observatory. The telescope allows automatic simultaneous spectroscopic and photometric observations and is scheduled to begin operation from Arizona in autumn 2013. Together with the telescope located in Borowiec, Poland, it will constitute a perfect instrument for nearly continuous spectroscopic observations of variable stars. With both instruments operational, the Global Astrophysical Telescope System will be established.

In this paper we present a few results from the first three years of an ongoing survey of globally-ordered magnetic fields in relatively faint (down to V ≈ 9) upper main sequence peculiar stars that we are conducting on the Dominion Astrophysical Observatory (DAO) Plaskett telescope. The DMFS uses the inexpensive DAO polarimeter module, dimaPol, mounted at the Cassegrain focus of the 1.8 m telescope to detect new magnetic stars and determine rotation periods and longitudinal magnetic field curves using medium-resolution (R ≈ 10,000) circular spectropolarimetry of both the Hβ line and metal lines in an approximately 280 Å wide wavelength region centered on Hβ. By concentrating on the mid-B to A-type peculiar stars, the DMFS provides an extension to the ‘Magnetism in Massive Stars’ (MIMES) Large Program which concentrated on similar field detections in more massive stars.

Precision asteroseismology is the determination of accurate stellar parameters from oscillation data. At first successful for pulsating white dwarf stars, it is now applied to more and more types of stars. We give a number of selected examples where precision asteroseismology, but also asteroseismology based on few observables may lead to considerable improvement of stellar astrophysics in the near future.

We present a study of photometric properties of very crowded stellar fields toward the Galactic Bulge. We performed a search for pulsating stars among thousands of variable stars from the OGLE-II survey supplementing the variability study with photometric measurements in four Johnson-Cousins UBVIC passbands. Using these data, we analysed the properties of objects located at different distances and, whenever possible, classified them.

Time-series of high-resolution spectra of massive main-sequence pulsators contain information on the degree l and azimuthal number m of a pulsation mode. I present an overview of existing mode-identification techniques that have been developed to derive l and m from spectroscopic data. I also discuss the data quality needed to perform such a study. Through some examples from the literature I show that the optimal way to identify modes in heat-driven non-radial pulsators is by 1) using multi-site campaign data, 2) combining different spectroscopic mode-identification techniques, and 3) combining results from photometric and spectroscopic mode-identification studies.

We developed an advanced binary system model that includes stellar oscillations on one or both stars, with the goal of mode identification by fitting of the photometric light curves. The oscillations are modeled as perturbations of the local surface temperature and the local gravitational potential. In the case of tidally distorted stars, it is assumed that the pulsation axis coincides with the direction connecting the centers of the components rather than with the rotation axis. The mode identification method, originally devised by B. Bíró, is similar to eclipse mapping in that it utilizes the amplitude, phase and frequency modulation of oscillations during the eclipse; but the identification is achieved by grid-fitting of the observed light curve rather than by image reconstruction. The proposed model and the mode identification method have so far been tested on synthetic data with encouraging results.

Thanks to the space missions CoRoT and Kepler new oscillation frequencies have been discovered in the Fourier spectra of Blazhko RR Lyrae stars. The period doubling (PD) yields half-integer frequencies between the fundamental mode and its harmonics. In many cases the first and/or second radial overtone frequencies also appear temporally. Some stars show extra frequencies that were identified as potential non-radial modes. We show here that all these frequencies can be explained by pure radial pulsation as linear combinations of the frequencies of radial fundamental and overtone modes.

We cannot presume to summarize all of the science we've discussed in the talks, posters, and informal discussions. Here, we discuss a few of the themes that emerged, concentrating on the theoretical basis that Wojtek Dziembowiski and his colleagues have developed and explored over the past 40+ years. We connect those with observational results – especially those from recent ground-based surveys and space-based missions that have revolutionized the study of stellar variability.

The All-Sky Automated Survey (ASAS) appeared to be extremely useful in establishing the census of bright variable stars in the sky. A short review of the characteristics of the ASAS data and discoveries based on these data and related to pulsating stars is presented here by an enthusiastic user of the ASAS data.

The role of magnetic field in late type stars such as proto-planetary and planetary nebulae (PPNe/PNe), is poorly known from an observational point of view. We present submillimetric observations realized with the Submillimeter Array (SMA) which unveil the dust continuum polarization in the envelopes of two well known PPNe: CRL 618 and OH 231.8+4.2. Assuming the current grain alignment theory, we were then able to trace the geometry of the magnetic field.