We present the results of an all sky survey for binary systems among the massive stars that we made with the HST Fine Guidance Sensors. The sample of 225 stars is comprised mainly of Galactic O- and B-type stars and Luminous Blue Variables, plus a few luminous stars in the LMC. The FGS TRANS mode observations are sensitive to detection of companions with an angular separation of 0.01–1 arcsec and brighter than △m = 5 mag. The FGS observations resolved 52 binary and 6 triple star systems and detected partially resolved binaries in 7 additional targets, yielding a companion detection frequency of 29%. We also gathered literature results on the numbers of close spectroscopic binaries and wider astrometric binaries among the sample. These results confirm the high multiplicity fraction. The period distribution is essentially flat in increments of log P, although there remains an observational gap in detections for periods of years and decades.

The wealth of data in the past decades, and especially in the past 15 years has transformed our picture of the gas around the Milky Way and other spiral galaxies. There is good evidence for extraplanar gas that is a few kpc in height and is seen in all gaseous phases: neutral; warm atomic; and hot, X-ray emitting gas. This medium is seen not only around the Milky Way, but other spiral galaxies and it is related to the star formation rate, so it is likely produced by the activity in the disk through a galactic fountain. More extended examples of halo gas are seen, such as the HVC around the Milky Way and around M 31. This gas is typically 10–20 kpc from the galaxy and is not seen beyond 50 kpc. This gas is most likely being accreted. A hot dilute halo (106 K) is present with a similar size, although its size is poorly determined.

An ongoing controversy surrounds the relative amounts of outflow from the disk and accretion onto galaxies such as the Milky Way. There is good evidence for accretion of cold material onto the Milky Way and other galaxies, but it is not clear if there is enough to modify the gas content and star formation properties in the disk. The reservoir of accretion material is as yet unidentified. Some of these findings may be related to the issue that galaxies are baryon-poor: their baryon to dark matter ratio is well below the cosmological value. The absence of baryons may be due to extremely violent outflow events in the early stages of galaxy formation. We may be able to understand this stage of galaxy evolution by applying our deepening understanding of our local disk-halo environment.

CoRoT is the first instrument aiming at detecting exoplanets from space, using the transit method. It has been built in order to explore the domain of planets with orbital period less than three months, and size down to about two Earth radii. Successfully launched on the 27th of December 2006, the instrument started its science observations by the beginning of February 2007. The first detections show the capability of the instrument to enlarge the parameter space and to explore the transition regime between gaseous giant and terrestrial planets. Five new transiting giant planets discovered by CoRoT are fully characterized at the time of writing.

We have chosen the name of GYES, one of the mythological giants with one hundred arms,offspring of Gaia and Uranus, for our instrument study of a multifibre spectrograph forthe prime focus of the Canada-France-Hawaii Telescope. Such an instrument could provide anexcellent ground-based complement for the Gaia mission and a northern complement to theHERMES project on the AAT. The CFHT is well known for providing a stable prime focusenvironment, with a large field of view, which has hosted several imaging instruments, buthas never hosted a multifibre spectrograph. Building upon the experience gained at GÉPIwith FLAMES-Giraffe and X-Shooter, we are investigating the feasibility of a highmultiplex spectrograph (about 500 fibres) over a field of view one degree in diameter. Weare investigating an instrument with resolution in the range 15 000 to 30 000, whichshould provide accurate chemical abundances for stars down to 16th magnitude and radialvelocities, accurate to 1 km s-1 for fainter stars. The study is led byGÉPI-Observatoire de Paris with a contribution from Oxford for the study of thepositioner. The financing for the study comes from INSU CSAA and Observatoire de Paris.The conceptual study will be delivered to CFHT for review by October 1st 2010.

I present a personal summary of the first ARENA conference on the prospects of building large astronomical infrastructures at the Concordia station in Antarctica, and my view on our progress to date in achieving this goal. Inparticular, I discuss the basic scientific, technical, and political conditions which I believe must be satisfied in order to develop a world-classinternational astronomical facility at Concordia.


This review covers a variety of topics related to the properties of Pre–Main Sequence stars in star forming regions, young clusters and associations. Some recent developments of theoretical models of PMS evolution are discussed, with emphasis on the role of magnetic fields in low-mass stars and their impact on observable quantities. Critical tests on the comparison between model predictions and observations are presented for stars across the mass spectrum. The issue of the formation and early evolution of massive stars is addressed, with emphasis on clustered versus isolated objects. After a brief historical background on the derivation of the Initial Mass Function, current representations of this quantity are discussed. The issue of the duration of the star formation process is dealt with using the results of age dating methods for young stars, mainly based on the property of Lithium depletion during PMS evolution. A recent analysis of the properties of the stellar population of the Orion Nebula Cluster is presented with the resulting IMF and age distributions. Finally, a discussion of recent determinations of the metallicity distribution of young stars in clusters and associations closes the review.

This chapter is a review of the dynamics of two-planet systems. It includes the study of averaged models of both secular and resonant planetary configurations. The introduction describes our understanding of long-term planetary behavior and stability. The next section introduces the presently known sample of 31 extra-solar systems and the classification of these systems with respect to their dynamical behavior. Their secular dynamics are described in Section 3, where we also introduce the main techniques commonly used for exploring dynamical features. We conclude this section by describing the effects of the proximity of a secular system to mean-motion resonances. Finally, phenomena related to mean-motion resonances are presented in Section 4.

We construct an approximate asymptotically flat stationary and axisymmetric vacuum metric by imposing matching conditions on an interior metric associated to a perfect fluid with equation of state µ+(1–n)p = µ0. A comparison between this vacuum metric and the Kerr one is made. Finally, a brief reflexion about the Wahlquist metric is commented in relation with our results.

This report aims to provide a summary of the status of our Antarctic Submillimetre Telescope (AST) project up to date. It is a very new project for Antarctic astronomy. Necessary prerequisites for a future deployment of a large size telescope infrastructure have been tested in years 2007 and 2008. The knowledge of the transmission, frost formation and temperature gradient were fundamental parameters before starting a feasibility study. The telescope specifications and requirements are currently discussed with the industrial partnership.

So as to prepare future observations of terrestrial extrasolar planets liable to shelter life, we attempt to detect the life on the Earth seen as a dot. We use the Moon Earthshine, in which any place reflects the totality of the enlightened part of Earth facing the Moon. Observing from OHP and from ESO, we detected terrestrial chlorophyll in the near infrared, the so-called Vegetation Red Edge, and this detection is larger when forests are present than when an ocean is mainly visible from the Moon. Only if observations are made from a high latitude location, and at some moments in the year, Earthshine can be observed during a large part of the day. During these long observing windows, different “landscapes" are facing the Moon. So the Earthshine corresponding to various parts of our Earth could be studied. Preliminary testing observations have been made at Concordia since the first winterover campaign and the LUCAS experiment has been set up.

Astronomy is in a golden age of discovery of the new, with a growingappreciation from astrophysics that physics has studied so far analmost insignificant fraction of reality. This golden age is enabledby technology, with next generation technologies approaching theGiga-euro/dollar investment level. This forces a strategic view of relativestrengths in the past, and strategies for future developments. Some ofthese may transcend traditional wavelength classifications.


The first suite of instruments and associated science cases for a larger facilityat Dome C are mainly targeted towards imaging and surveys.While the potential advantages for astronomical observations fromAntarctica are applicable to both imaging and spectroscopy,spectrographs are more complex to build and harder to use in afully automatic and remote operation.However, the innovative technique of 3D-Spectroscopy (3DS) offersimaging and spectroscopic capabilities simultaneously withapplications to a wide range of astronomical programmes.Furthermore, 3DS provides several operational benefits, that are well suited for a location such as Antarctica.

The Large Magellanic Cloud (LMC) is the closest large satellite of the Milky Way (MW) and the first step of the extragalactic distance scale, hence knowing the distance to the LMC and its three-dimensional structure contributes to the definition of the entire cosmic distance ladder. RR Lyrae stars are old objects which trace the halo of the LMC. They can be used as distance indicators because they follow a period-luminosity-metallicity (PLKsZ) relation in the Ks passband. The purpose of this study was the derivation of a new PLKsZ relation for RR Lyrae stars in the LMC based on the multi-epoch Ks photometry obtained by the VISTA survey of the Magellanic Clouds system (VMC, Cioni et al. 2011).

We discuss the various post-main sequence phases of massive stars,focusing on Wolf-Rayet stars, Luminous Blue Variables, plus connectionswith other early-type and late-type supergiants. End states for massive stars are also investigated, emphasising connections between Supernovae originating fromcore-collapse massive stars and Gamma Ray Bursts.

Two exercises are proposed to illustrate the simple linear regression. The first one is based on the famous Galton's data set on heredity. We use the lm R command and get coefficients estimates, standard error of the error, R2, residuals …In the second example, devoted to data related to the vapor tension of mercury, we fit a simple linear regression, predict values, and anticipate on multiple linear regression.

This pratical session is an excerpt from practical exercises proposed by A. Dalalyan at EPNC (see Exercises 1 and 2 of http://certis.enpc. fr/∼dalalyan/Download/TP_ENPC_4.pdf).

In this brief review we discuss how some of our basic understanding of chemical processes in interstellar medium has received a boost from the Herschel Space Observatory. With Herschel in operations for over 1 year, it is still early to discuss the full impact of new results and instead I demonstrate the new science enabled by near-complete spectroscopic access to sub-millimeter to far-infrared wavelengths.

Due to the recent interest shown by astronomers towards the Antarctic Plateauas a potential site for large astronomical facilities, we assistedin the last years to a strengthening of site testing activities in this region, particularly at Dome C. Most of the results collected so far concern meteorologic parameters and optical turbulence measurements based on different principles using different instruments. At present we have several elements indicating that, above the first $20{-}30$ m, the quality of the optical turbulence above Dome C is better than above whatever other site in the world. The challenging question, crucial to know which kind of facilities to build on, is to establish how much better the Dome C is than a mid-latitude site. In this contribution we will provide some complementary elements and strategies of analysis aiming to answer to this question. We will try to concentrate the attention on critical points, i.e. open questions that still require explanation/attention.

During its mission Gaia will give access to a so far never reached astrometric accuracy of a large number of Solar System objects. Nevertheless some of these Gaia observations could be efficiently completed by ground-based observations. This will allow us to get a better understanding of the dynamical and physical properties of these objects. We present a general overview of these cases.

Magnetic fields have been detected at the surface of many stars, where they are responsible for various activity phenomena, and presumably they are present also in their deep interior. They channel stellar winds to large distance, thus increasing the loss of angular momentum. In stably stratified radiation zones, they tend to impose uniform rotation, and may thus interfere with the rotational mixing operating in these regions and influence the evolution of the host star. Moreover, certain magnetic configurations are known to be unstable, and they could produce some mixing of their own. We shall discuss these problems in the light of the latest developments.