NGC 6611, Trumpler 14, Trumpler 15, Trumpler 16, and Collinder 232 are very young open clusters located in star-formation regions in the Eagle Nebula and Carina in the Milky Way, and NGC 346 in the Small Magellanic Cloud. With different instrumentation and techniques, it has been possible to detect and classify new Herbig Ae/Be and classical Be stars and to provide new tests/comparisons of the Be stars' appearance models. Special (He-strong) stars in these star-formation regions are also discussed.

We describe the methodology required for estimation of photometric estimates of metallicity based on the SDSS gri passbands, which can be used to probe the properties of main-sequence stars beyond ~10 kpc, complementing studies of nearby stars from more metallicity-sensitive color indices that involve the u passband. As a first application of this approach, we determine photometric metal abundance estimates for individual main-sequence stars in the Virgo Overdensity, which covers almost 1000 deg2 on the sky, based on a calibration of the metallicity sensitivity of stellar isochrones in the gri filter passbands using field stars with well-determined spectroscopic metal abundances. Despite the low precision of the method for individual stars, internal errors of σ[Fe/H]~0.1 dex can be achieved for bulk stellar populations. The global metal abundance of the Virgo Overdensity determined in this way is 〈[Fe/H]〉 = −2.0±0.1 (internal) ±0.5 (systematic), from photometric measurements of 0.7 million stars with heliocentric distances from ~10 kpc to ~20 kpc. A preliminary metallicity map, based on results for 2.9 million stars in the northern SDSS DR-7 footprint, exhibits a shift to lower metallicities as one proceeds from the inner- to the outer-halo population, consistent with recent interpretation of the kinematics of local samples of stars with spectroscopically available metallicity estimates and full space motions.

In a survey of 18 nearby Seyfert nuclei, we find evidence for geometrically thick gas disks on scales of tens of parsecs. Mapping the interstellar medium traced by H2 ν = 1–0 S(1) emission using the infrared integral field spectrometers OSIRIS and SINFONI reveals general disk rotation with an additional significant component of random bulk motion implied by the high local velocity dispersion. The size scale of the typical nuclear gas disk is ~30 pc in radius with a comparable vertical height, and the distribution and kinematics suggest the gas is spatially mixed with the nuclear stellar population. Based on the estimated characteristic gas mass fraction of 10%, the average gas mass within this region is ~107M⊙. This suggests column densities of NH ~ 5 × 1023 cm−2, but the significantly lower densities implied by the stellar continuum extinction indicate that the gas distribution on these scales is dominated by dense clumps. We discuss the feasibility of constraining the masses of the central black holes via modeling of the gas disk kinematics, highlighting the importance of properly accounting for the gas velocity dispersion, and the use of these direct mass estimates to calibrate masses derived from the method of reverberation mapping.

Using the ESO NTT/SUSI2 telescope, we observed TWA22AB during five different observing runs over 1.2 years to measure its trigonometric parallax and proper motion. HARPS at the ESO 3.6m telescope was also used to measure the system's radial velocity over 2 years. Based on trigonometric-parallax, proper-motion and radial-velocity measurements, we re-analyzed the membership of TWA22AB of the young, nearby associations TW Hydrae, β Pictoris and Tucana–Horologium.

To present a summary of IAU Symposium 265 it is perhaps best to first step back and ask the question “Why did we meet in Rio to discuss chemical abundances?”. Part of the scientific rationale was to host a meeting that brought together researchers who probe chemical abundances and chemical evolution in all of the different astrophysical environments. All meetings should be planned such that they have an outcome and, with such a diverse set of abundance specialists brought together in one place to talk about their favorite topics, the stated outcome for IAUS265 was to provide, within our current understanding of the universe, a unified picture of the production of chemical elements over cosmic time; such a view is what I think of as cosmochemistry.

We report on preliminary results of spectroscopic determination of the atmospheric parameters and chemical abundances of the parent stars of the recently discovered transiting planets CoRoT-2b and CoRoT-4b. We found a flat distribution of the relative abundances as a function of their condensation temperatures. Also, we introduce a new methodology to investigate a relation between the abundances of these stars and the internal migration of their planets.

We present a strong correlation between 12μm mid-IR and intrinsic X-ray (2–10 keV) luminosities of local Seyferts. This work is based on new diffraction-limited mid-IR observations with the 8-m Very Large Telescope (VLT), resulting in the least-contaminated core fluxes of 42 Seyferts to date.

Fluid disks and tori around black holes are discussed within different approaches and with the emphasis on the role of disk gravity. We first review the prospects for investigating the gravitational field of a black hole–disk system by analytical solutions of stationary, axially symmetric Einstein equations. More detailed considerations are focused on the middle and outer parts of extended disk-like configurations where relativistic effects are small and the Newtonian description is adequate. As an example, we investigate the case of a torus near a massive black hole that is a member of the black-hole binary system.

We present new evidence of X-ray absorption variability on time scales from a few hours to a few days for several nearby bright AGNs. The observed NH variations imply that the X-ray absorber is made of clouds eclipsing the X-ray source with velocities in excess of 103 km s−1, and densities, sizes and distances from the central black hole typical of BLR clouds. We conclude that the variable X-ray absorption is due to the same clouds emitting the broad emission lines in the optical/UV. We then concentrate on the two highest signal-to-noise spectra of eclipses, discovered in two long observations of NGC 1365 and Mrk 766, and we show that the obscuring clouds have a cometary shape, with a high density head followed by a tail with decreasing NH. Our results show that X-ray time resolved spectroscopy can be a powerful way to directly measure the physical and geometrical properties of BLR clouds.

The mean angular momentum associated with the collision of two celestial objects moving in almost circular heliocentric orbits was studied. The results of these studies were used to develop models of the formation of binaries at the stage of rarefied preplanetesimals. The models can explain a greater fraction of binaries formed at greater distances from the Sun. Sometimes there could be two centers of contraction inside the rotating preplanetesimal formed as the result of a collision between two rarefied preplanetesimals. Such formation of binaries could result in binaries with almost the same masses of components separated by a large distance. Formation of a disk around the primary could result because the angular momentum that was obtained by a rarefied preplanetesimal formed by collision was greater than the critical angular momentum for a solid body. One or several satellites of the primary could be formed from the disk.

We claim that in the starburst environment there is no accretion of the ISM onto the BH and thus, in such cases, the BH luminosity is regulated by the mass-loss rate from massive stars in the star forming region. We calculate the accretion rate and show that it is usually small during the superwind stage and grows at the post-starburst stage, when the matter reinserted by intermediate–mass stars remains gravitationally bound and fuels the central BH.

The light elements Li, O, Na, Al, and Mg are known to show star-to-star variations in the globular clusters 47 Tuc and NGC 6752. We have investigated the behavior of the α element sulfur, for which no previous measurements exist in any Galactic globular cluster. We used high-resolution UVES spectra of Si multiplet 1 around 923 nm, and determined S abundances by means of ATLAS static plano-parallel models. NLTE corrections were applied and 3D corrections were also computed from co5bold 3D hydrodynamical models. Sulfur has been measured in four subgiant stars in NGC 6752, leading to an average value of [S/Fe] = +0.49 ± 0.15 dex, consistent with what is observed in field stars of similar metallicity. In 47 Tuc, we measured S in four turnoff (TO) and five subgiant (SG) stars, for an average value of [S/Fe] = 0.18 ± 0.14 dex. While the measurement errors are consistent with a constant value among all cluster stars analyzed, we detected a highly significant correlation with sodium abundance, as well as a tentative one with silicon. The sulfur–sodium correlation is difficult to explain in terms of nucleosynthesis. Given its high statistical significance, it is also difficult to dismiss it as fortuitous. Until better data for more stars are available, the question as to its origin remains open.

The primary goal of the sacy project (Search for Associations Containing Young Stars) was to identify possible associations of stars younger than the Pleiades association among optical counterparts of ROSAT X-ray-bright sources. The study of the chemical abundance in stars located in regions of stellar formation is extremely important to understand stellar nucleo-synthesis, the physical mechanisms controlling mixing in stellar interiors, and chemical enrichment in the Galaxy. The present work highights the first results of a chemical-abundance study of evolved stars identified in the sacy survey. For this, we performed a detailed spectroscopic analysis for the determination of atmospheric parameters and Li abundance for a sample of giant and subgiant stars. The observations were carried out with high resolution using the FEROS (R = 48 000) échelle spectrograph. We measured the stellar parameters (Teff, log g, vmic, [Fe/H]) from LTE analysis in the complete range of 420-1100 nm. Li abundance was derived from the region around the lithium line at 6707.78 Å for the entire sample of stars.

We review two main scenarios that may have implanted Sedna, 2004 VN112 and 2000 CR105 on their current peculiar orbits. These scenarios are based on perihelion lifting mechanisms that acted upon primordial scattered icy bodies. Supposing that the Sun was formed in a dense star cluster and that the gas giants were also forming while the cluster was still dense, an inner Oort cloud that includes Sedna at its inner edge could have been formed by the circularization of icy leftovers orbits scattered by the gas giants. A putative planetary mass solar companion can also produce a similar population of icy bodies through a perihelion lifting mechanism induced by secular resonances from the companion. A third scenario also dependent on a primordial dense cluster may contribute to adding a significant number of extrasolar icy bodies to the main solar component of the population created by the cluster model. These extrasolar objects are transferred to Sun orbits from the scattered disk of passing stars that were numerous in the dense primordial environment. We compare the scenarios as to the orbital distribution of the induced populations as well as their total mass. We conclude that both the cluster model and the solar companion model can produce icy body populations consistent with Sedna's orbit. It is also quite possible that this inner Oort cloud may be composed of roughly one tenth of extrasolar objects.

It has been known for some time that elliptical galaxies have some form of dust structure at their centers (Kormendy & Djorgovski 1989; van Dokkum & Franx 1995). Nevertheless the exact amount and the origin of the dust is still unknown. In a previous paper, we have shown that all early-type galaxies hosting an AGN have dust at their centers as opposed to only a quarter of the inactive galaxies in a pair-matched sample (Simões Lopes et al. 2007). Here we use Spitzer (IRAC and MIPS) observations of the same sample — 32 active and 32 inactive early-type galaxies — and state-of-the-art spectral modelling from Draine & Li (2007) to estimate the dust mass present in these galaxies. We have also created PAH images by estimating and subtracting the stellar-only contribution to the flux at the 7.9 μm image from the 3.6 μm image.

The coronal mass ejection (CME) link to geomagnetic storms stems from the southward component of the interplanetary magnetic field contained in the CME flux ropes and in the sheath between the flux rope and the CME-driven shock. A typical storm-causing CME is characterized by (i) high speed, (ii) large angular width (mostly halos and partial halos), and (iii) solar source location close to the central meridian. For CMEs originating at larger central meridian distances, the storms are mainly caused by the sheath field. Both the magnetic and energy contents of the storm-producing CMEs can be traced to the magnetic structure of active regions and the free energy stored in them.

A galaxy's metallicity provides a record of star formation, gas accretion, and gas outflow, and is therefore one of the most informative measurements that can be made at high redshift. It is also one of the most difficult. I review methods of determining chemical abundances in distant star-forming galaxies, and summarize results for galaxies at 1 ≲ z ≲ 3. I then focus on the mass-metallicity relation, its evolution with redshift, and its uses in constraining inflows and outflows of gas, and conclude with a brief discussion of future prospects for metallicity measurements at high redshift.

An analysis is well underway for the data from the second Large Program (PI M. A. Barucci) dedicated to investigating the surface properties of Centaurs and Transneptunian objects through spectroscopic, photometric color, lightcurve, and polarimetric observations using the European Southern Observatory (ESO) Very Large Telescope (VLT) and New Technology Telescope (NTT). 45 objects were observed between 2006 and 2008, allowing a broad characterization of at least the largest and brightest objects among this population. In this report, we summarize all our findings, but focus on the analysis of the presence of ices such as methane, ethane, nitrogen, ammonia hydrate, methanol, and particularly H2O which is so abundant throughout the outer solar system.

The cometary nature of the 1908 Tunguska cosmic body is compatible with the predictions of an analytical theory of the 1908 Tunguska explosion developed in 1976–1979. The theory takes into account the three simultaneously occurring processes, namely aerodynamic destruction of the cosmic body in the Earth's atmosphere, transversal expansion of the crushed mass under the action of pressure gradient on the frontal surface of the body, and an aerodynamic deceleration of crushed expanding mass. The use, for the mechanical parameters of the Tunguska cosmic body, of the characteristics of a cometary nuclei such as that of comet Halley 1986 III and comet Shoemaker – Levy 9 1994, gives parameters of the Tunguska explosion derived from observations of Tunguska event in the Siberian taiga in 1908.

We present CCD BVIKC photometry in the field of the open cluster NGC 2587. We developed a new method to clean statistically the colour–magnitude diagrams. NGC 2587 is found to be slightly younger than the Hyades and probably of solar metallicity. From 18 probable members with measured proper motions, we derived the following mean cluster values: μα = −4.3 ± 3.6 mas yr−1 and μδ = −2.5 ± 3.4 mas yr−1. Colour excesses, E(B − V) = 0.10 and E(V − I) = 0.15 mag, and a heliocentric distance of 3.7 ± 0.7 kpc are obtained. The interstellar extinction in the cluster direction is found to follow the normal reddening law.