The astronomical seeing from the Antarctic high plateau site Dome Chas been a matter of speculation for over a decade. During 2004 wemade the first wintertime measurements of the seeing using a MultiAperture Scintillation Sensor (MASS), a device that is well-suited forautomated unattended operation. The mean seeing was found to be 0.27 arcsec, and the seeing is better than 0.15 arcsec for 25% ofthe time. These extraordinarily low levels of turbulence make Dome C asuperb site for future optical and infrared telescopes.

Direct observations of gravitational waves will open in the nearfuture new windows on the Universe. Among the expected sources,instabilities of rotating compact astrophysical objects are waited tobe detected with some impatience as this will sign the birth of“gravitational waves asteroseismology”, a crucial way to improve ourknowledge of matter equation of state in conditions that cannot bereproduced in a lab. However, the theoretical work needed to reallyget informations from to-be-detected signals is still quite large, numericalsimulations having become a necessary key ingredient. This articletries to provide a short overview of the main physical topics involvedin this field (general relativity, gravitational waves, instabilitiesof rotating fluids, etc.), concluding with a brief descriptionof the work that was done in Paris-Meudon Observatory by SilvanoBonazzola and collaborators.

Gaia will provide accurate parallaxes, spectrophotometry and spectroscopy for hundreds of thousands of emission-line stars across the whole HR diagram. In preparation for the Gaia mission, we are developing algorithms to recognize and classify emission-line stars. A large collection of ground-based spectroscopic observations has been collected and will be used for testing and training the algorithms.

Gaia will also provide information on several millions of early-type stars. Determining accurate parameters for these stars from Gaia data only will be difficult due to the AV – Teff degeneracy.

Gaia mission is underway conducting its 5 year lasting survey of the sky. At the moment the commissioning period has been completed and half a year worth of routine phase data has been collected. The status of the mission is outlined with short explanation of some commissioning phase findings and their impact on the mission. With a few examples of early mission data the potential of Gaia is demonstrated and we can conclude that the mission is capable meeting its high expectations.

This paper reviews recent continuum surveys done at (sub)millimeter wavelengths towards z>3.7 quasars and observations of the CO line emission in high z sources.

ASTEP South is an Antarctic Search for Transiting ExoPlanets in the South pole field, from the Concordia station, Dome C, Antarctica. The instrument consists of a thermalized 10 cm refractor observing a fixed 3.88° × 3.88° field of view to perform photometry of several thousand stars at visible wavelengths (700–900 nm). The first winter campaign in 2008 led to the retrieval of nearly 1600 hours of data. We derive the fraction of photometric nights by measuring the number of detectable stars in the field. The method is sensitive to the presence of small cirrus clouds which are invisible to the naked eye. The fraction of night-time for which at least 50% of the stars are detected is 74% from June to September 2008. Most of the lost time (18.5% out of 26%) is due to periods of bad weather conditions lasting for a few days (“white outs”). Extended periods of clear weather exist. For example, between July 10 and August 10, 2008, the total fraction of time (day+night) for which photometric observations were possible was 60%. This confirms the very high quality of Dome C for nearly continuous photometric observations during the Antarctic winter.

In recent years, a large amount of data has been collected with the aim to quantify the day- and nighttime astronomical observing conditions at Dome C. The available data show that the precipitable water vapor is below 0.75 mm in general, thus offering very good conditions for sub-mm observations. The extremely low temperatures of the atmosphere cause a very low background in the thermal infrared, which leads to significant savings in the time required to carry out large observing programmes. The absence of strong turbulence in the upper atmosphere results in a low scintillation and poses favorable conditions for photometric programmes. The free atmosphere seeing is of the order of $0\farcs 36$, but optical observations are impaired by the occurrence of a very strong turbulent boundary layer which reaches up to median altitudes of some 23 m in winter and up to some 400 m in summer. Detailed measurements of the vertical and temporal variation of the various parameters are now needed, in order to draw robust conclusions about short- and long-term stabilities and trends, and to constrain the specifications of future instruments that are eventually being deployed at Dome C.

Our aim is to present new unified line profiles of sodium perturbed by H2 from the optical to the infrared spectral range. We compare the specific results obtained for the 3s-3p transition to laboratory spectra.

The most remarkable future possibilities of stellar spectroscopy and abundanceanalysis are discussed, and their consequences for the further understanding of stellar nucleosynthesis are commented on. It is argued that it will soonbe possible to put the exploration of the origin of the chemical elements andthe study of the chemical evolution of galaxies on a solid empirical ground,through systematic observations of yields from AGB stars and planetary nebulae,Wolf-Rayet stars and supernovae, and of well-determined abundance trends in different stellar populations.

An experiment designed for measuring the electronic spectra of PAH cations and PAH cluster cations has been set up, which is briefly described. The photodissociation spectra, reflecting the absorption spectra, of 2-methyl-naphthalene dimer cation have been recorded in the spectral ranges corresponding to the transitions from the ground state to both the excited charge resonance state and the first allowed local electronic excitation state.

In the framework of the DCMB (Développement Concerté de Matrices de Bolomètres) collaboration we develop low temperature bolometer arrays for large field, high resolution imaging in astrophysics. DCMB is a R&D effort funded by CNES and CNRS involving a number of French laboratories. Two parallel developments have been made in this collaboration based on the NbSi alloy either semi-conducting or superconducting depending on the Nb concentration. Multiplexing schemes have been developed and demonstrated for these two options. Here we focus on high impedance bolometers and present two examples of array developments in progress: first, a 23 pixels array for the balloon-borne instrument OLIMPO and, second, 204 pixels for ground based observations with the 30 m IRAM telescope.

In this paper, I review most of the current knowledge about magnetic field topologies and surface differential rotation of cool active stars like the Sun. I concentrate in particular on the most recent observationalresults, derived from studies on dynamo field generation in stellar convectiveenvelopes from magnetic imaging of very active rapidly rotating low mass stars, and present the elements of evidence that dynamo processes in these active stars are distributed throughout the whole convective zone, rather than being confined in a thin interface layer as in the Sun.I finally discuss the new discovery that dynamo magnetic fields generate feedback effects on the global dynamics of stellar convective envelopes.

Resonance broadening is important for the hydrogen lines in the spectra of F-type and later stars. In the corresponding temperature regime, the extended wings of the Balmer lines are used as a stellar effective temperature indicator. We show the effect of the use of two broadening theories, Ali & Griem (1965, 1966) and Barklem et al. (2000a, 2000b), on the effective temperature derived in non-LTE from Hα and Hβ in the Sun and the metal-poor star HD19445. Van der Waals broadening is important for strong spectral lines in the atmospheres of F-type and later stars. For the selected transitions in Ca I and Ca II, line profile comparisons are made between applying the van der Waals damping constants from laboratory measurements, the ABO perturbation theory, and the classic Unsöld approximation.

High-precision radial velocity measurements have suffered from stellar spots effects for more than one decade. With the advent of high-resolution infra-red spectrographs, one is allowed to move into a new spectral domain where the influence of these stellar phenomena on measurements is significantly reduced. 
We present the first results of our CRIRES campaign on TW Hya, around which a periodic optical radial velocity variation was found and attributed to a planet. Our work showed that the signal is not present in the infra-red, pointing to a cold spot instead of to a planet as the explanation for the different data sets. This campaign demonstrates the power of this new approach and shows that CRIRES can deliver high-precision radial velocity measurements.

The paper starts from the rationale, already presented in 2004 at the firstToulouse meeting on astronomy at Dome C, to propose an infrared, wide-fieldImaging FTS (IFTS) as a first generation instrument behind a 2 to 3 moptical telescope. Such an instrument could fully take advantage of all theproperties of the site for imagery and spectroscopy and offer an instrumentpresently needed after the numerous imaging surveys. Simulations have beenconducted to define the range of field size and of resolution which couldbe reachable. Then, derived from the study of H2 Explorer (H2EX) an IFTSfor a space project, an optical design for a 2 to 25 μm instrument,imaging a 10'×10' field, has been developed, based on a dual ouputinterferometer, using cat's eyes retroreflectors in its arms. With amaximum optical path difference (OPD) of 30 cm a spectral resolution of105 at 2 μm (20 000 at 25 μm) is possible with this fieldsize, behind a PILOT-type telescope (2.4 m) and a minimum beam size of80 mm within the interferometer. With the same optics and the samemechanism of control of the OPD, two interchangeable beamsplitters (2 to5.5 μm and 6 to 25 μm) and the corresponding detector arrays (InSband Si:As) cover the entire spectral range. Theinstrument must be cryogenic (temperature around 50 K) to make the thermalbackground from the optics negligible. The best sensitivity is obtainedthrough narrow-band filters (2%) isolating lines in emission-lineregions. Such a survey instrument has never been built before. It calls fora dedicated telescope for the best use of this type of instrument on theDome C site.

The conditions of thermodynamic equilibrium, local thermodynamic equilibrium, and statistical equilibrium are discussed in detail. The equations of statistical equilibrium and the supplementary equations are shown together with the expressions for radiative and collisional rates with the emphasize on the solution for trace elements.

We discuss models of AGB star atmospheres. Special emphasis is put onthe question of opacities, treatment of radiative transfer andsimulation of interferometric results.

In this lecture I try to explain the basic concepts related to fluidmotions when a background rotation dominates the flows.In particular, the notions of geostrophic flow, Ekman layer, Ekmancirculation are explained. However, the main focus of this lecture is onthe eigenmodes which occur in such a context and I emphasize here thespecial effects conveyed to inertial and gravito-inertial modesby the hyperbolic nature of the governing operators. A final sectionintroduces the case of the elliptic instability which I recentlysuggested as one of the processes of binary synchronization.

The standard model of stellar structure is unable to account for various observational facts, such as anomalies in the surface composition, and there is now a broad consensus that some extra mixing must occur in the radiation zones, in addition to the always present convective overshoot or penetration. The search for the causes of this extra mixing started in the late seventies, and it was quickly realized – in particular by Sylvie Vauclair and her co-workers – that some mild turbulence must be present to counteract the effect of gravitational settling and radiative levitation. What could be responsible for this turbulence? One suggestion was the internal gravity waves emitted at the boundary of convection zones, but it is still not established whether these waves will lead to true mixing. However they transport angular momentum, and therefore they generate differential rotation, which may be shear-unstable and thus lead to turbulence. Another way to transport angular momentum and produce an unstable rotation profile is through the large-scale circulation which is induced by the structural adjustments as the star evolves, or by the torques applied to it (due to stellar wind, accretion, tides). These processes participate in what is called the “rotational mixing”; their implementation in stellar evolution codes – again under Sylvie's impulse – has given birth to a new generation of stellar models, which agree much better with the observational constraints, although there is still room for improvement.