Gravitational lensing provides a strict test of cosmogonic models. We use fully non-linear numerical propagation of light rays through a model universe with inhomogeneities derived from a particular cosmogonic model, i.e. three-dimensional lensing simulations, to study its lensing properties. As a first example we present results for the standard CDM scenario. The lensing test for this model predicts that we should have seen far more widely split quasar images than have been found.

The solar photosphere is the outer boundary of the cavity which defines the spectrum of the global p-modes. It is also the lowest layer that permits direct observation of the boiling mixture of motions which eventually create the complex patterns apparent in the chromosphere and corona. Studies of the dynamical behaviour of this layer are therefore of paramount importance for an overall understanding of the dynamic sun.

The various modes of spallative LiBeB production are summarized, and classified according to their dependence or independence on the abundance of medium heavy elements (CNO) illustrated by that of oxygen in the interstellar medium. The predictions of the models are confronted to the available observational correlations (Be, B vs O). Clearly, a primary mechanism should lead to a slope one in the lg(Be/H) vs [O/H] plot and a secondary mechanism to a slope two. Due to the ambiguity of the O data, another criterion, based on energetics, can help us to select an adequate model. A purely secondary origin in the very early Galaxy is much more energy demanding than a primary one. Indeed, magnesium seems to be a possible surrogate of oxygen and iron since i) it is spectroscopically more easy to cope with and ii) its nucleosynthetic yield is independent of the mass cut and does not depend on metallicity.

It is well known that the outcome of case B evolution of the primaries of massive close binary systems (M1 ≥ 9 M⊙) depends on the initial primary mass. The most massive primaries finally ignite carbon, form iron cores and presumably end in a supernova explosion, whereas the lighter ones presumably end as white dwarfs, without carbon ignition. This paper derives an estimate of the mass boundary separating these two kinds of evolution.

As an example of the first case, the evolution of a 20 M⊙ + 14 M⊙ system was computed; after the mass exchange, the primary star (with M = 5.43 M⊙) evolves through the helium-burning (Wolf-Rayet) stage towards a supernova explosion; finally the system evolves into an X-ray binary (BWRX-evolution).

As a representative for the second case the evolution of a 10 M⊙ + 8 M⊙ system was examined. After the first stage of mass exchange, the primary (with a mass of 1.66 M⊙) approaches the helium main sequence; during later phases of helium burning the radius increases again, and a second stage of mass transfer starts; after this the star (with a mass of 1.14 M⊙) again evolves towards the left in the Hertzsprung-Russell diagram and ends as a white dwarf (BSWD-evolution). A system of 15 M⊙ + 8 M⊙ is found to evolve very similar to the 20 M⊙ + 14 M⊙ system. The mass Mu, separating the two types of evolution, must therefore be situated between 10 and 15 solar masses. An initial chemical composition X = 0.70, Z = 0.03 was used for all systems.

The ionized hydrogen regions seen on monochromatic Hα photographs of nearby spiral galaxies (e.g. Fig. 1) can be divided into four classes (Monnet, 1971): (1) bright, condensed, classical HII regions; (2) diffuse emission in the arms surrounding and connecting the classical regions (emission measure (EM) ∼ 150 cm−6 pc, for a gas electron temperature of 6000 K); (3) much fainter, diffuse emission extending over the entire disk (EM ∼ 50 cm−6 pc) in most Sc and Sd galaxies; (4) diffuse emission in the nuclear region.

The location of Planetary Nebulae Nuclei (PNNi) on the H-R diagram is a very important clue to understand the evolution of these objects.

The well-known shell star Pleione is also an interesting variable star, BU Tau. Its variability was first discovered by Calder (1937) from photoelectric observations in the 1930's. The light curve of this star from the end of the 19th century to 1954 was studied by Binnendijk (1949, 1955). Botsula and Sharov (1959) and Sharov (1961) added some old and new observations and continued the light curve up to 1959.

In this review a critical examination of our present knowledge about the structure and evolution of central stars of planetary nebulae is presented. In particular, the still enigmatic origin of the Wolf-Rayet central stars is addressed, too. Some directions for future work are given at the end.

Radial velocity observations of λ Eridani between 1971 and 1980 and uvbyHα photometry in 1977 show that the star is both a light and velocity variable with a period of 0.701538 d. Copernicus observations in 1977 are compatible with this result. Both the radial velocity and photometric amplitude are variable, and these variations may be correlated with the hydrogen emission line strength. The character and phasing of the light and velocity curves suggest that λ Eridani is a pulsating variable.

Brown dwarfs are intermediate objects between planets and stars. The lower end of the brown-dwarf mass range overlaps with the one of massive planets and therefore the distinction between planets and brown-dwarf companions may require to trace the individual formation process. We present results on new potential brown-dwarf companions of Sun-like stars, which were discovered using CORALIE radial-velocity measurements. By combining the spectroscopic orbits and Hipparcos astrometric measurements, we have determined the orbit inclinations and therefore the companion masses for many of these systems. This has revealed a mass range between 25 and 45 Jupiter masses almost void of objects, suggesting a possible dividing line between massive planets and sub-stellar companions.

Recent precise observations of the microwave and submillimeter cosmic background radiation are summarized, including rocket experiments, the FIRAS (Far InfraRed Absolute Spectrophotometer) on the COBE, CN results, and microwave measurements. Theoretical implications are summarized.

Knowing the distance of an astrophysical object is key to understanding it. However, at present, comparisons of theory and observations are hampered by precision (or lack thereof) in distance measurements or estimates. Putting the many recent results and new developments into the broader context of the physics driving cosmic distance determination is the next logical step, which will benefit from the combined efforts of theorists, observers and modellers working on a large variety of spatial scales, and spanning a wide range of expertise. IAU Symposium 289 addressed the physics underlying methods of distance determination across the Universe, exploring the various approaches employed to define the milestones along the road. The meeting provided an exciting snapshot of the field of distance measurement, offering not only up-to-date results and a cutting-edge account of recent progress, but also full discussion of the pitfalls encountered and the uncertainties that remain. One of the meeting's main aims was to provide a roadmap for future efforts in this field, both theoretically and observationally.

We know that each of the Galilean satellites of Jupiter has a tenuous atmosphere by terrestrial standards. Io’s SO2 equatorial atmosphere and, perhaps, Callisto’s atmosphere inferred from its large ionospheric densities are measured in nanobars, whereas the atmospheres of Europa and Ganymede produced by ion sputtering of the water ice surfaces only reach picobar pressures and are comprised mostly of O2. Io’s polar atmosphere is probably an order of magnitude less dense than its equatorial atmosphere. Europa and Ganymede have O2 atmospheres with column densities in the range of (1-10)×1014cm−2. These atmospheres, on the basis of their inferred production and loss rates, are estimated to have short residence times of ~2-3 days.

The basic concept of what a Be star is we owe to Struve (1931). His proposal that these stars are rapidly rotating and have an extended, disc-like, circumstellar envelope is still the basis for all models of Be stars. Unfortunately, progress in understanding the dynamics of Be stars has been painfully slow, a consequence of the very complex nature of the problem. As yet there does not exist a self-consistent unique model of any Be star.

Recent HST spectra indicate that a large fraction of Seyfert 1 galaxies have UV absorption lines that are intrinsic to the active nucleus or its environment. IUE monitoring or multiple HST observations of several sources show that many absorption lines are variable, either as a result of mass motion across the line-of-sight or of changing ionization within the gas in response to variations in the ionizing continuum. The UV absorbers may be related to the warm absorbers seen in the X-ray spectra of many Seyfert galaxies, but a direct connection between the two has not been made. Some of the absorption lines may arise in the emission-line regions in the nucleus or host galaxy, providing valuable clues to their nature.

Cliver & Ling (2010) recently suggested that the solar wind had a floor or ground-state magnetic field strength at Earth of ~2.8 nT and that the source of the field was the slow solar wind. This picture has recently been given impetus by the evidence presented by Schrijver et al. (2011) that the Sun has a minimal magnetic state that was approached globally in 2009, a year in which Earth was imbedded in slow solar wind ~70% of the time. A precursor relation between the solar dipole field strength at solar minimum and the peak sunspot number (SSNMAX) of the subsequent 11-yr cycle suggests that during Maunder-type minima (when SSNMAX was ~0), the solar polar field strength approaches zero - indicating weak or absent polar coronal holes and an increase to nearly ~100% in the time that Earth spends in slow solar wind.

Since 1978 85 new objects have been classified as planetary nebulae. They are listed in Table 1 which gives the designations, names, coordinates and the references to the discovery. In the list of misclassified planetary nebulae (Table 2) 33 objects have been included. Principal criteria have been summarized which can help to distinguish planetaries from other objects. They refer to observable properties and are valid only in a statistical sense.

The UVES Paranal Observatory Project (POP), is an ESO public database of about 400 stars whose high quality spectra were obtained with UVES, the high resolution spectrometer of the VLT. All stars were observed with two instrument modes, in order to cover almost completely the optical region (300–1000 nm). The resolving power is about 80000, and for most of the spectra, the typical S/N ratio is 300–500 in the V band. Program stars fall into two groups, stars belonging to open clusters IC2391 and NGC6475, and bright field stars. For field stars, the only selection criterion applied was to cover the largest possible variety of spectral types in the HR diagram, including peculiar objects, e.g., Ap and Bp stars, Wolf-Rayet stars, Be stars, carbon stars and metal poor stars. The spectra have been reduced, coadded and merged and various products can be downloaded from a public area. For each star the final spectrum may be displayed through a dedicated user-friendly Spectral Preview Interface. The database is accessible at http://www.eso.org/uvespop

A first analysis of a deep blind HI survey covering the southern Zone of Avoidance plus an extension towards the north (196† ≤ ℓ ≤ 52†) obtained with the Multibeam receiver at the 64-m Parkes telescope reveals slightly over a thousand galaxies within the latitude completeness limit of |b| ≤ 5†. The characteristics and the uncovered large-scale structures of this survey are described, in particular the prominence of the Norma Supercluster, the possible cluster around PKS 1343–601 (both in the Great Attractor region), as well as the Local Void and the clustering in the Puppis region. In this blind HI survey HIZOA J0836–43 was discovered, one of the most massive spiral galaxies known to date (MHI = 7.3 × 1010 M⊙, MT = 1.1 × 1012 M⊙; H0 = 75 km/s/Mpc). Although of similar mass to Malin 1-like objects, this galaxy does not share their typical low-surface brightness properties, but seems an exceptionally massive but normal, high surface brightness, star-forming galaxy.