Despite the number of known exoplanets increasing on an almost weekly basis, the question as to whether exoplanets host moons remains unanswered. Exomoons could be potential seats for life, as well as improving our understanding of planetary formation and celestial mechanics. Here we summarize our findings from an investigation into how detectable habitable-zone exomoons are with Kepler-class photometry.

In recent years our knowledge of star, brown dwarf and planet formation has progressed immensely due to new data in the IR domain (Spitzer telescope), new X-ray campaigns such as the Chandra Orion Ultradeep Project (COUP) and the X-ray Emission Survey of Taurus (XEST), with XMM-Newton, as well as adaptive optics results and synoptic studies of young stellar and substellar objects.

Trained as a physicist, George W. Wetherill (1925-2006) made seminal contributions to the fields of geochemical dating, meteoritical and asteroidal science, and the theory of the formation of terrestrial planets, evolving along the way into one of the first astrobiologists.

Early-type galaxies do not come in any shape, form, and color. Many of their observable properties obey tight correlations, also known as empirical scaling relations. The correlations are non-trivial, in the sense that they cannot be explained by simple physical or dimensional arguments. A subset of the empirical scaling relations connects baryonic observables with quantities that depend on the total gravitational potential of the galaxies, and thus on their dark matter content. These correlations are a fundamental testbed for our understanding of the formation and evolution of early-type galaxies, and, more in general, of the physical processes that determine the interplay between baryons and dark matter at galactic scales.

Simultaneous timing of several pulsars distributed over the sky, so called Pulsar Timing Array (PTA), is used for a variety of metrological and astronomical applications. Three examples of PTA application are presented: link between celestial reference frames, ensemble pulsar time scale and detection of gravitational waves.

In this review I gave an overview of the structure and evolution of protoplanetary disks, and how the evolution of dust affects this. This is an important topic because these determine the conditions under which planets are formed, or were formed in our solar system 4.5 billion years ago.

Star forming galaxies often exhibit hot halos with structures that resemble chimneys and fountains extending for several kpc above the galaxy. Observations indicate that they are probably produced by supernovae (SNe) which blow superbubbles that carve holes in the disk. Through these holes, high speed material is injected and expands buoyantly up to a maximum height and then returns to the disk pulled by the galaxy gravity. This circulating gas in a fountain tends to condense out forming high-velocity clouds and filaments. Starburst galaxies also show evidence that the spectacular winds that arise from their disk are fed by SNe explosions. Similarly, at galaxy cluster scales, most massive clusters exhibit rich filamentary structure of ionized gas which is distributed all around the central galaxy. We discuss here the role that SNe bubbles play in driving outflows and filamentary structures both at galaxy and galaxy-cluster scales. With the help of HD and MHD numerical simulations, we show in particular that SN-driven turbulence may play a key role at helping a central AGN halting and ”isotropize” the cooling flow in the central regions of a galaxy cluster.

We show that the peculiar surface abundance patterns of Carbon Enhanced Metal Poor (CEMP) stars has been inherited from material having been processed by H- and He-burning phases in a previous generation of stars (hereafter called the “Source Stars”). In this previous generation, some mixing must have occurred between the He- and the H-burning regions in order to explain the high observed abundances of nitrogen. In addition, it is necessary to postulate that a very small fraction of the carbon-oxygen core has been expelled (either by winds or by the supernova explosion). Therefore only the outermost layers should have been released by the Source Stars. Some of the CEMP stars may be He-rich if the matter from the Source Star is not too much diluted with the InterStellar Medium (ISM). Those stars formed from nearly pure ejecta would also be Li-poor.

The Standard Model and General Relativity provide a good description of phenomena at low energy. These theories, which agree very well with the experiment, contain a set of parameters called “fundamental constants”, that are assumed invariant under changes in location and reference system. However, their possible variation has been studied since Dirac made the large numbers hypothesis (LNH). Moreover, unified field theory and extra dimensions theories such as Kaluza-Klein or Superstring theories, state not only the variation of these constants, but also the simultaneity of the variations.

The Eötvös effect is one of the most sensitive indicators of changes in fundamental constants. Bekenstein (2002) showed that in his theory, using a classical static particle model of matter, there is no Eötvös effect and therefore met the Universality of Free Fall and the Principle of Equivalence.

We present different results than those obtained by Bekenstein, Kraiselburd, Vucetich (2009). Modifying his theory, taking more realistic models of matter and using the model THεμ techniques (Ligtman-Lee (1975) and Haugan (1979), not used before to analyze this model), very small but measurable effects have been found.

It is well known that stars orbited by giant planets have higher abundances of heavy elements when compared with average field dwarfs. A number of studies have also addressed the possibility that light element abundances are different in these stars. In this paper we will review the present status of these studies. The most significant trends will be discussed.

A Galactic model of stellar population synthesis is used along with a genetic algorithm to reconstruct the three dimensional dust distribution in the Milky Way. We have applied this technique towards over 1500 IRDC cloud candidates, for which we recovered distances and masses for 1259 of them. Aside from giving us the distance to the dust, the three dimensional extinction map also provides us with a temperature independent measure of its density. This new method is independent of any kinematical information, thus providing a new way to obtain information on the Galactic distribution of the ISM. It is a good complement to existing measures which are solely based on molecular gas kinematics as both methods are completely independent and both are affected by different systematics. It will be able to provide valuable distance information for use in the analysis and interpretation of far-infrared and sub-millimetre observations by Herschel and Planck. In the future it could be used with deeper stellar observations or observations at longer wavelengths in order to probe even higher density clouds and to even larger distances.

We performed numerical simulations to study the secular orbital evolution and dynamical structure of the quintuplet planetary system 55 Cancri using the self-consistent orbital solutions of Fischer et al. (2008).

Chemically peculiar (CP) stars exhibit, simultaneously, a wide variety of physical phenomena, including diffusion, convection, magnetism, and pulsation. Thus, progress in the understanding of these objects requires the input of researchers from a variety of research fields within stellar astrophysics. The General Assembly of the IAU, in Rio de Janeiro, provided an excellent opportunity to discuss challenging new results faced in CP star research and improve the exchange of information and cooperation with experts of neighbouring scientific fields.

We present MHD numerical simulations of a rotating turbulent convection system in a 3D domain (we have used the finite volume, Goudunov type MHD code PLUTO (Mignone et al. 2007)). Rotating convection is the natural scenario for the study of the dynamo action which is able to generate a large scale magnetic field, like the observed in the sun. Though we have neglected in the present approach the Ω effect, due to a large scale shear, our model is appropriate to test the controversial existence of the so called α effect that arises from helical turbulence (e.g. Cattaneo & Hughes 2006, Käpylä et al. 2009). We start with a two-layer piece-wise polytropic region in hydrostatic equilibrium (e.g. Ziegler 2002), considering one stable overshoot layer at the bottom and a convectively unstable layer at the top of the computational domain. We have allowed this hydrodynamic system to evolve up to the steady state, i.e., after about 10 turnover times (τ). Then, we introduced a seed magnetic field and let the system evolve for more ~40 τ. Our preliminary results are summarized below in Figure 2.

Using the test-field method for nearly irrotational turbulence driven by spherical expansion waves it is shown that the turbulent magnetic diffusivity increases with magnetic Reynolds numbers. Its value levels off at several times the rms velocity of the turbulence multiplied by the typical radius of the expansion waves. This result is discussed in the context of the galactic mean-field dynamo.

Post-AGB (pAGB) objects are low to intermediate initial mass (≤8 M⊙) objects that have terminated normal nuclear burning and as a result are undergoing rapid evolution toward the white dwarf sequence. In classical pAGB objects evolution is to hotter effective temperatures at roughly constant luminosity. However, there are also several classes of pAGB objects that have revived nuclear burning after approaching or being on the white dwarf sequence. These include objects with delayed final helium shell flashes (e.g. Sakurai's star) and white dwarf mergers (e.g. R CrB stars). Binary evolution plays a critical role in many of these systems. A group of pAGB supergiants with large infrared excesses are suspected to be binaries that have undergone common envelope evolution. Further details on many of these objects can be found in reviews, see for instance Van Winckel (2003) and Herwig (2005).

The binary fraction in the sub-stellar regime is a topic of discussion. The lower masses of ultra cool dwarfs (UCDs) with respect to the other stars make them even more important because a measurable effect on their radial velocity (RV) or luminosities can be caused by extremely low mass companions. Some UCDs in young star forming regions are bright enough to be studied with existing high resolution instrumentation. The UCDs are intrinsically faint in the optical and the optical RV measurements are affected by “rotationally modulated inhomogeneous surface features” that can mimic a companion, while the near-infrared (NIR) RVs are less prone to them. Therefore, we decided to monitor the RV of six UCDs in the NIR. Blake et al. (2007) demonstrated RV measurement accuracy of 300-600 m s−1 in the NIR using telluric calibration.

Highly collimated supersonic jets and outflows are very frequent in several astrophysical environments. They are seen in young stellar objects (YSOs), proto-planetary nebulae, compact objects (like galactic black holes or microquasars, and X-ray binary stars), active galactic nuclei, and are also possibly associated to gamma-ray bursts (GRBs) and to ultra-high energy cosmic rays sources (UHECRs). Despite their different physical scales, all these outflow classes have strong morphological similarities, but questions such as - what physics do they share? - or - can we find a universal mechanism of acceleration and collimation that operates in all classes? - remain matters of debate. The most accepted mechanism for their origin relies on a rotating accretion disk threaded by perpendicular large-scale magnetic fields and, though most of the systems producing jets contain an accretion disk around the central source, the real role that rotation and magnetic fields play in these processes is still not fully understood, nor are the highly non-linear physical processes connected to these jet-disk systems in the large parameter space involved.

Interactions with close stellar or planetary companions can significantly influence the evolution and lifetime of protoplanetary disks. It has recently become possible to search for these companions, directly studying the role of multiplicity in protoplanetary disk evolution. We have described an ongoing survey to directly detect these stellar and planetary companions in nearby star-forming regions. Our program uses adaptive optics and sparse aperture mask interferometry to achieve typical contrast limits of Δ K=5-6 at the diffraction limit (5–8 MJup at 5–30 AU), while also detecting similar-flux binary companions at separations as low as 15 mas (2.5 AU). In most cases, our survey has found no evidence of companions (planetary or binary) among the well-known “transitional disk” systems; if the inner clearings are due to planet formation, as has been previously suggested, then this paucity places an upper limit on the mass of any resulting planet. Our survey also has uncovered many new binary systems, with the majority falling among the diskless (WTTS) population. This disparity suggests that disk evolution for close (5–30 AU) binary systems is very different from that for single stars. As we show in Figure 1, most circumbinary disks are cleared by ages of 1–2 Myr, while most circumstellar disks are not. These diskless binary systems have biased the disk frequency downward in previous studies. If we remove our new systems from those samples, we find that the disk fraction for single stars could be higher than was previously suggested.

We derive the 3D-NLTE lithium abundance in the solar photosphere from the Lii line at 670 nm as measured in several solar atlases. The Li abundance is obtained from line profile fitting with 1D/3D-LTE/3D-NLTE synthetic spectra, considering several possibilities for the atomic parameters of the lines blending the Li feature. The 670 nm spectral region shows considerable differences in the two available disc-centre solar atlases, while the two integrated disc spectra are very similar. We obtain A(Li)3D–NLTE = 1.03. The 1D-LTE abundance is 0.07 dex smaller. The line-lists giving the best fit for the Sun may fail for other stars, while some line-lists fail to reproduce the solar profile satisfactorily. We need a better knowledge of the atomic parameters of the lines blending the Li feature in order to be able to reproduce both the solar spectrum and the spectra of other stars. An improved line-list is also required to derive reliable estimates of the isotopic Li ratio in solar-metallicity stars.