Polycyclic aromatic hydrocarbons are a class of molecules of broad interest that has longbeen explored by various spectroscopic techniques. The electronic spectroscopy of thesespecies is of particular interest since it provides a framework for the understanding ofthe electronic structure of large polyatomic molecules. Such studies also allow thesystematic investigation of electronic relaxation mechanisms in large molecules. In thisreview, we focus on the gas-phase experimental work on such systems and present the latestprogress. We also underline the challenges that remain to be tackled. A focus on theunderstanding of the electronic relaxation pathways at work in gas-phase PAHs will also bepresented, as well as their possible manifestation in space.

We analyze the long-term tidal evolution of a single-planet system through the use of numerical simulations and averaged equations giving the variations of the semi-major axis and eccentricity of the relative orbit. For different types of planets, we compute the variations due to the planetary and stellar tides. We then calculate the critical value of the eccentricity for which the stellar tide becomes dominant over the planetary tide. The timescales for orbital decay and circularization are also discussed and compared.

In the past years a wealth of observations has unraveled the structural properties of the Dark and Luminous mass distribution in spirals. These have pointed out to an intriguing scenario not easily explained by present theories of galaxy formation. The investigation of individual and coadded objects has shown that the spiral rotation curves follow, from their centers out to their virial radii, a Universal profile (URC) that arises from the tuned combination of a stellar disk and of a dark halo. The importance of the latter component decreases with galaxy mass. Individual objects, on the other hand, have clearly revealed that the dark halos encompassing the luminous discs have a constant density core. This resulting observational scenario poses important challenges to presently favored theoretical ΛCDM Cosmology.

Helioseismic inferences have demonstrated very clearly the importance of including element diffusion and settling in solar modelling: models incorporating these processes are in substantially better agreement with the inferred solar sound speed than are models that neglect them. The remaining discrepancy between the models and the Sun has been taken as evidence for mixing in the region just beneath the convection zone. However, rather more serious discrepancies have resulted from a revision of solar abundances, and no obvious solution to this problem has been found so far. This perhaps demonstrates the danger of complacency when dealing with so complex a thing as a star. Hydrodynamical instabilities are likely to play a more important role than acknowledged in standard stellar modelling. An interesting example, if not relevant to modelling up to the present solar age, is the possible onset of semiconvective instability just beneath the convection zone, as first emphasized by Bahcall et al. (2001).


In this talk we present the latest results from our ongoing project on geometro-thermodynamics (also known as information geometry of thermodynamics or Ruppeiner geometry) of dilaton BHs in 4D in both Einstein and string frames and a dyonic dilaton BH and at the end we report very briefly results from this approach to the 2D dilaton BHs.

Image reconstruction from interferometric data is an inverse problem. Owing to the sparse spatial frequency coverage of the data and to missing Fourier phase information, one has to take into account not only the data but also prior constraints. Image reconstruction then amounts to minimizing a joint criterion which is the sum of a likelihood term to enforce fidelity to the data and a regularization term to impose the priors. To implement strict constraints such as normalization and non-negativity, the minimization is performed on a feasible set. When the complex visibilities are available, image reconstruction is relatively easy as the joint criterion is convex and finding the solution is similar to a deconvolution problem. In optical interferometry, only the powerspectrum and the bispectrum can be measured and the joint criterion is highly multi-modal. The success of an image reconstruction algorithm then depends on the choice of the priors and on the ability of the optimization strategy to find a good solution among all the local minima.

The IR emission cascade from the pyrene cation due to a broad band optical excitation issimulated using kinetic Monte Carlo. Anharmonicities of the ground electronic statepotential energy surface are taken into account in the transition energies, themicrocanonical densities of states, and the rate of hydrogen loss through variousstatistical theories. The emission spectral features of the “3.3”, “6.2” and “11.2”μm bands are computed for different blackbody temperatures.

Moderately close binaries are a special class of targets for planet searches. From a theoretical standpoint, their hospitality to giant planets is uncertain and debated. From an observational standpoint, many of these systems present technical difficulties for precise radial-velocity measurements and classical Doppler surveys avoid them accordingly. In spite of these adverse factors, present data support the idea that giant planets residing in binary and hierarchical systems provide unique observational constraints on the processes of planet formation and evolution. The interest and the importance of including various types of binary stars in extrasolar planet studies have thus grown over time and significant efforts have recently been put into: (i) searching for stellar companions to the known planet-host stars using direct imaging, and (ii) extending Doppler planet searches to spectroscopic and moderately close visual binaries. In this contribution we review the observational progress made over the past few years in the detection and study of extrasolar planets in binary systems, putting special emphasis on the two developments mentioned above.

In this contribution, we summarize the recent progress made in recording laboratoryinfrared (IR) spectra of protonated polycyclic aromatic hydrocarbon molecules(H+PAH) in the gas phase. The IR spectra of a large variety ofH+PAH species ranging from benzene to coronene have been obtained by variousvariants of photodissociation spectroscopy. The employed techniques include single-photonIR photodissociation (IRPD) of tagged H+PAH ions and IR multiple-photondissociation (IRMPD) of bare H+PAH ions. The comparison of the laboratory IRspectra with astronomical spectra supports the hypothesis that H+PAH ions arepossible carriers of the unidentified IR emission (UIR) bands. Moreover, the spectraprovide detailed information about the geometric and electronic structure as well as thechemical reactivity and stability of these fundamental hydrocarbon ions.

Numerous hydrogenated molecules observed in comets and the interstellar medium present nuclear spin isomers. The non-thermal ortho: para ratios measured in space are believed to be of high diagnostic value, allowing remote measurement of physical conditions prevailing in the past, such as the initial temperature associated with a molecular formation or condensation. The lack of laboratory studies on interactions at the gas-solid interface limits our current interpretation of observations. Recent progress in nuclear spin conversion (NSC) dynamics are discussed in this paper. Results on water and methane in cryogenic matrices illustrate the conversion mechanisms within the condensed phase at very low temperatures. NSC of molecular hydrogen at the surface of 10 K Amorphous Solid Water (ASW) shows surface mediated conversion processes for molecular hydrogen. NSC involving molecular ices are discussed in the light of few recent studies, including UV photodesorption investigations.

Massive stars in their late stages of evolution as Red Supergiants experience mass loss. The resulting winds show various degrees of dynamical and chemical complexity and produce molecules and dust grains. This review summarises our knowledge of the molecular and dust components of the wind of Red Supergiants, including VY CMa and Betelgeuse. We discuss the synthesis of dust as a non equilibrium process in stellar winds, and present the current knowledge of the chemistry involved in the formation of oxygen-rich dust such as silicates and metal oxides.

Over 300 extrasolar planets have been found since 1992, showing that planetary systems are common and exhibit an outstanding variety of characteristics. As the number of detections grows and as models of planet formation progress to account for the existence of these new worlds, statistical studies and confrontations of observation with theory allow to progressively unravel the key processes underlying planet formation. In this chapter we review the dominant contribution of Doppler spectroscopy to the present discoveries and to our general understanding of planetary systems. We also emphasize the synergy of Doppler spectroscopy and transit photometry in characterizing the physical properties of transiting extrasolar planets. As we will see, Doppler spectroscopy has not reached its limits yet and it will undoubtly play a leading role in the detection and characterization of the first Earth-mass planets.

This chapter is intended to provide a general presentation of the atomic andnuclear processes responsible for X-ray line and gamma-ray line emission invarious astrophysical environments. I consider line production from hotplasmas, from accelerated particle interactions, from the decay ofradioactive nuclei synthesized in stars and from positron annihilation.Spectroscopic properties of these emissions are discussed in the light ofthe detection capabilities of modern space instruments.

Angular momentum transport in accretion disk has been the focus of intense research in theoretical astrophysics for many decades. In the past twenty years, MHD turbulence driven by the magnetorotational instability has emerged as an efficient mechanism to achieve that goal. Yet, many questions and uncertainties remain, among which the saturation level of the turbulence. The consequences of the magnetorotational instability for planet formation models are still being investigated. This lecture, given in September 2012 at the school “Role and mechanisms of angular momentum transport in the formation and early evolution of stars” in Aussois (France), aims at introducing the historical developments, current status and outstanding questions related to the magnetorotational instability that are currently at the forefront of academic research.

We present “A STEP”, a project dedicated to the search for planetarytransits from Antartica. The project consists of a fully automatic 40 cm telescope equipped with an 11-million-pixel CCD installed atDome C. The site offers crucial assets for a ground-based exoplanettransit search: uninterrupted phase coverage and excellentseeing. 
This system would be able to detect hot Jupiters transiting in frontof stars as faint as magnitude sixteen and could also detect smallerplanets in close-in period around brighter stars. Our estimations,based on results of previous surveys are an average of 6 detectionsper 60 days survey. Compared to existing surveys, this excellent yieldis due to the nearly-continuous phase coverage and excellent seiing.This short term project is meant to be a photometric qualifyer for thesite and the first stage of a massive detection campaign. A mid-termobjective of 1000 detections for 2012 could be achieved either with manysmall telescopes or with a large Schmidt telescope with a large fieldof view. 
The project is relatively simple and cost-effective, and has thedouble purpose of qualifying the site and obtaining first-classscientific results. Our team is already familiar with transitdetection with an automated telescope (BEST) and cold temperaturequalification.

We discuss the physics and the evolution of a typical massive star passing through an evolutionary stage similar to that of Betelgeuse. After a brief introduction recalling various observed parameters of Betelgeuse, we discuss the Pre-Main-Sequence phase (PMS), the Main-Sequence (MS) phase, the physics governing the duration of the first crossing of the HR diagram, the red supergiant stage (RSG), the post-red supergiant phases and the final fate of solar metallicity stars with masses between 9 and 25 M⊙. We examine the impact of different initial rotation and of various prescriptions for the mass loss rates during the red supergiant phase. We show that, whatever the initial rotation rate (chosen between 0 and 0.7 × υcrit, υcrit being the surface equatorial velocity producing a centrifugal acceleration balancing exactly the gravity) and the mass loss rates during the RSG stage (varied between a standard value and 25 times that value), a 15 M⊙ star always ends its lifetime as a RSG and explodes as a type II-P or II-L supernova.

I review driving mechanisms for stellar winds, using first the example of the coronal, pressure-driven solar wind, but then focussing mainly on radiation-pressure driven winds from hot, luminous stars.For the latter, I review the central role of line-opacity as a coupling between matter and radiation, emphasizing how the Doppler shift of an accelerating wind outflow exposes the strong line opacity toa substantial continuum flux, and thus allows the line force to sustain the outward acceleration against gravity.Through the CAK formalism that assumes a power-law distribution of line-opacity, I derive the mass loss rate and wind velocity law, and discuss how these are altered by various refinements like a finite-disk correction, ionization variations in opacity, and a non-zero sound speed.I also discuss how multiline scattering in Wolf-Rayet (WR) winds can allow them to exceed the single scattering limit, for which the wind and radiative momenta are equal. Through a time-dependent perturbation analysis, I show how the line-driving leads to a fast, inward "Abbott-wave" mode for long wavelength perturbations, and a strong Line-Deshadowing-Instability at short wavelengths, summarizing also 1D and 2D numerical simulations of the nonlinear evolution of this instability.I next discuss how rapid stellar rotation alters the latitudinal variation of mass loss and flow speed, and how this depends on treatment of gravity darkening, nonradial line forces, and "bi-stability" shifts in ionization.Finally, I conclude with a discussion of the large mass loss epochs of Luminous Blue Variable (LBV) stars, and how these might be modeled via super-Eddington, continuum driving moderated by the "porosity" associated with extensive spatial structure.

This review describes five categories of the reactions of polycyclic aromatichydrocarbons, including photochemistry, electron attachment/detachment, recombinationprocesses, radical reactions, and ion-neutral chemistry. For each class of reaction, anoverview of the studies and their general results are presented, as well as references tothe literature. The thermochemistry of PAHs and relevant species is described, includingbond dissociation energies, ionization energies, electron affinities, basicities,acidities, and the interrelationships of these quantities. Modeling of the chemistry ofPAHs and their ions is discussed for both diffuse and dark clouds. The role of PAH cationsin the catalytic formation of molecular hydrogen is considered. Finally, this reviewconcludes with a discussion of current challenges in the chemical characterization ofPAHs, and a perspective for future studies.


The Low Frequency Array is a new radio telescope based on phased arrayprinciples that will operate at frequencies from 10–240 MHz. The vastimprovement in sensitivity and resolution over previous instrumentsthat have worked at these frequencies, together with the increasedflexibility that results from the phased array approach(multi-beaming, no moving parts) make LOFAR an extremely versatile andpowerful new instrument. We present some of the scientific drivers andgive an overview of the current design.


We present detailed chemical abundances of Fe, Ca and Ba for 17 globular clusters (GCs) in 5 Local Group dwarf galaxies: NGC 205, NGC 6822, WLM, the SMC and LMC. These abundances are part of a larger sample of over 20 individual elements measured in GCs in these galaxies using a new analysis method for high resolution, integrated light spectra. Our analysis also provides age and stellar population constraints. The existence of GCs in dwarf galaxies with a range of ages implies that there were episodes of rapid star formation (SF) throughout the history of these galaxies; the abundance ratios of these clusters suggest that the duration of these burst varied considerably from galaxy to galaxy. We find evolution of Fe, Ca, and Ba with age in the LMC, SMC, and NGC 6822 that is consistent with extended, lower-efficiency SF between bursts, with an increasing contribution of low-metallicity AGB ejecta at late times. Our sample of GCs in NGC 205 and WLM are predominantly old and metal-poor with high [Ca/Fe] ratios, implying that the early history of these galaxies was marked by consistently high SF rates.