The Pioneer 10/11 spacecraft yielded the most precise navigation in deepspace to date. However, their radio-metric tracking data has consistentlyindicated the presence of a small, anomalous, Doppler frequency drift. Thedrift is a blue-shift, uniformly changing with a rate of ~6 × 10-9 Hz/s and can be interpreted as a constant sunward acceleration ofeach particular spacecraft of aP = (8.74 ± 1.33) × 10-10 m/s2. The nature of this anomaly remains unexplained. Here wesummarize our current knowledge of the discovered effect and review some ofthe mechanisms proposed for its explanation. Currently we are preparing forthe analysis of the entire set of the available Pioneer 10/11 Doppler datawhich may shed a new light on the origin of the anomaly. We present apreliminary assessment of such an intriguing possibility.


Polycyclic Aromatic Hydrocarbons (PAHs) are the most likely carriers proposed to account for the Aromatic Infrared Bands observed in emission between 3.3 and 12.7 μm, fulfilling both the chemical (presence of CC and CH aromatic bonds) and excitation constraints. We explain here how the emission spectrum of such species in astronomical environments can be modelled, to obtain for each infrared band both its intensity and its detailed profile.
The PAH model suffers from the lack of identification of individual species. Two strategies are described here that are currently being used to progress in this identification process. The first idea is that features in the far IR are much more specific to the exact molecular identity. Therefore their search with the coming Herschel Space Observatory will provide an unambiguous way to identify these molecules through their IR emission. Second, a reflection on where interstellar PAHs come from and how they evolve due to environmental conditions (UV irradiation, gas and dust interactions) is also necessary to get more insights into the nature of interstellar PAH candidates. In particular, recent studies have emphasized a chemical link between PAHs and very small grains in photodissociation regions.
Finally, we illustrate in this paper how progress in this field can only be attained by a synergy between astronomical observations, fundamental studies, both theoretical and experimental, and models.

Theoretical models of the equation of state (EOS)of neutron-star matter (starting with the crustand ending at the densest region of the stellar core) are reviewed. Apart froma broad set of baryonic EOSs, strange quark matter, and even more exotic (abnormaland Q-matter) EOSs are considered. Results of calculations of Mmaxfor non-rotating neutron stars and exotic compact stars are reviewed, withparticular emphasis on the dependence on the dense-matter EOS. Rapid rotationincreases Mmax, and this effect is studied for both neutron stars and exoticstars. Theoretical results are then confronted with measurements of masses of neutronstars in binaries, and the consequences of such a confrontation and their possible impacton the theory of dense matter are discussed.

The prospects of using extreme relativistic laser-matter interactions for laboratory astrophysics are discussed. Laser-driven process simulation of matter dynamics at ultra-high energy density is proposed for the studies of astrophysical compact objects and the early universe.

We review the significant role played by red supergiants (RSGs) in stellar populations, and some challenges and questions they raise for theoretical stellar evolution. We present how metallicity and rotation modify the way stars go to the red part of the Hertzsprung-Russell diagram or come back from it, and how RSGs might keep a trace of their main-sequence evolution. We compare theoretical population ratios with observed ones.

Tides come from the fact that different parts of a system do not fall in exactly the same way in a non-uniform gravity field. In the case of a protoplanetary disk perturbed by an orbiting, prograde protoplanet, the protoplanet tides raise a wake in the disk which causes the orbital elements of the planet to change over time. The most spectacular result of this process is a change in the protoplanet's semi-major axis, which can decrease by orders of magnitude on timescales shorter than the disk lifetime. This drift in the semi-major axis is called planetary migration, and is the most important aspect of planet–disk interactions. In this chapter, we first describe how the planet and disk exchange angular momentum and energy at the Lindblad and corotation resonances. Next we review the various types of planetary migration that have so far been contemplated: type I migration, which corresponds to low-mass planets (less than a few Earth masses) triggering a linear disk response; type II migration, which corresponds to massive planets (typically at least one Jupiter mass) that open up a gap in the disk; “runaway” or type III migration, which corresponds to sub-giant planets that orbit in massive disks; and stochastic or diffusive migration, which is the migration mode of low- or intermediate-mass planets embedded in turbulent disks. Third, we discuss questions linked to the planet eccentricity, in particular how the eccentricity is affected by the planet–disk interaction. Fourth, we discuss the various numerical schemes that have been used to describe planet–disk interactions. We discuss their strengths and weaknesses, and list the results that numerical simulations have achieved over the past decade.

I review efforts to determine the form and any lower limit to the initial mass function in the Galactic disk, using observations of low-mass stars and brown dwarfs in the field, young clusters and star forming regions. I focus on the methodologies that have been used and the uncertainties that exist due to observational limitations and to systematic uncertainties in calibrations and theoretical models. I conclude that whilst it is possible that the low-mass IMFs deduced from the field and most young clusters are similar, there are too many problems to be sure; there are examples of low-mass cluster IMFs that appear to be very discrepant and the IMFs for brown dwarfs in the field and young clusters have yet to be reconciled convincingly.

The infrared (IR) spectra of many galactic and extragalactic objects are dominated byemission features at 3.3, 6.2, 7.7, 8.6 and 11.2 μm, generally attributedto the IR fluorescence of Polycyclic Aromatic Hydrocarbon molecules (PAHs). These PAHbands have been found in a wide variety of environments throughout theUniverse and containup to 10% of the total power output of star-forming galaxies.

Ground-based telescopes, the Infrared Space Observatory (ISO) and the Spitzer SpaceTelescope revealed a plethora of weaker PAH bands and provided extensive evidence forsignificant variability in the PAH spectrum from source to source and spatially withinsources. Here we review the spectral characteristics of astronomical PAHs, theirdependence on the local physical conditions and the implications for the physical andchemical characteristics of the carriers.

The status of kinematic observations in Local Group dwarf spheroidalgalaxies (dSphs) is reviewed. Various approaches to the dynamicalmodelling of these data are discussed and some general features ofdSph dark matter haloes based on simple mass models are presented.

We find that deviation from the virial equilibrium of the Abell Cluster A586 yields evidence of the interaction between dark matter and dark energy. We argue that this interaction might imply a violation of the Equivalence Principle. These evidences are found in the context of two different models of dark energy-dark matter interaction.

After a brief introduction into the asteroseismic modelling of stars, we provide a compilation of the current seismic estimates of the core overshooting parameter and of the rotational frequency of single and binary massive stars. These important stellar parameters have meanwhile become available for eleven OB-type stars, among which three spectroscopic pulsating binaries and one magnetic pulsator. We highlight the potential of ongoing and future analyses of eclipsing binary pulsators as essential laboraties to test stellar structure and evolution models of single and binary stars.

The new astrochemistry experiment PIRENEA is presented.The set-up was designed to approach the physical conditionsthat prevail in the interstellar medium. It enables to performoriginal studies in particular when large molecules andnano-sized particles are involved. The experiment is nowoperational for science.

We present a new multi-fluid, grid-based magnetohydrodynamics (MHD) code PIERNIK, which is based on the Relaxing Total Variation Diminishing (RTVD) scheme. The original scheme has been extended by an addition of dynamically independent, but interacting fluids: dust and a diffusive cosmic ray (CR) gas, described within the fluid approximation, with an option to add other fluids in an easy way. The code has been equipped with shearing-box boundary conditions, a selfgravity module, an Ohmic resistivity module, as well as other facilities which are useful in astrophysical fluid-dynamical simulations. The code is parallelized by means of an MPI library. In this paper we briefly introduce the basic elements of the RTVD MHD algorithm, following Trac & Pen (2003) and Pen et al.  (2003), and then focus on a conservative implementation of the shearing-box model, constructed with the aid of Masset's (2000) method. We present the results of a test example of the formation of a gravitationally bound object (a planet) in a self-gravitating and differentially rotating fluid.

Binarity is often invoked to explain peculiarities that can not be explained by the standard theory of stellar evolution. Detecting orbital motion via the Doppler effect is the best method to test binarity when direct imaging is not possible. However, when the orbital period exceeds length of a typical observing run, monitoring often becomes problematic. Placing a high-throughput spectrograph on a small semi-robotic telescope allowed us to carry out a radial velocity survey of various types of peculiar evolved stars. In this review we highlight some findings after the first four years of observations. Thus, we detect eccentric binaries among hot subdwarfs, barium, S stars, and post-AGB stars with disks, which are not predicted by the standard binary interaction theory. In disk objects, in addition, we find signs of the on-going mass transfer to the companion, and an intriguing line splitting, which we attribute to the scattered light of the primary.

Herschel opens the possibility to detect the low-frequency vibrationalbands of individual polycyclic aromatic hydrocarbon (PAH) molecules and therefore toprogress in our understanding of the nature of these species and the properties of theenvironments from which they emit. However, unless one individual molecule dominates thePAH family, this detection will not be straightforward and it is necessary to optimise theobservational search with an educated guess of the band profiles and intensities. Sucheducated guess can be obtained from models that include a detailed description of themolecular properties (anharmonicity, rotation...) in the modelling of the cooling cascadeof the emitting species. First results are expected soon from the observation of the OrionBar as part of the HEXOS Herschel key program.

Stellar evolution theory has been extraordinarily successful at explaining the different phases under which stars form, evolve and die. While the strongest constraints have traditionally come from binary stars, the advent of asteroseismology is bringing unique measures in well-characterised stars. For stellar populations in general, however, only photometric measures are usually available, and the comparison with the predictions of stellar evolution theory have mostly been qualitative. For instance, the geometrical shapes of isochrones have been used to infer ages of coeval populations, but without any proper statistical basis. In this chapter we provide a pedagogical review on a Bayesian formalism to make quantitative inferences on the properties of single, binary and small ensembles of stars, including unresolved populations. As an example, we show how stellar evolution theory can be used in a rigorous way as a prior information to measure the ages of stars between the Zero Age Main Sequence and the Helium flash, and their uncertainties, using photometric data only.

AMBER is the near I.R. focal instrument of the VLTI. It recombines 3 beams simultaneously and has spectral resolution capability allowing simultaneous spectrum, visibilities, differential visibilities, closure phase and differential phases measurements on the observed sources. We present here the general formalism used on AMBER in order to compute differential phases and differential visibilities, in complement to the article of Tatulli et al. (2006). We show that these differential observables have precisions close to the fundamental noises and we present an illustration of model-fitting using them on the binary star γ2 Velorum where we made a precise measurment of the astrometry of the 2 components (3.65±0.1 mas). 


Opening talk of the Conference and acknowledgments.

During the five years of the mission, the Gaia spectrograph, the Radial Velocity Spectrometer (RVS) will repeatedly survey the celestial sphere down to magnitude V ~ 17–18. This talk presents: (i) the system which is currently developed within the Gaia Data Processing and Analysis Consortium (DPAC) to reduce and calibrate the spectra and to derive the radial and rotational velocities, (ii) the RVS expected performances and (iii) scientific returns.