A substantial number of stars was detected in the ROSAT All Sky Survey. Analysis of these data indicates a systematic shift in the distribution of their X-ray hardness ratios, from late type dwarfs to late type giants to early type stars, that can be attributed to systematic differences in line-of-sight absorption.

The physical parameters of HII regions span orders of magnitude in scale. The classes most closely linked to star formation are the smallest, densest, and, presumably, youngest stages: compact, ultracompact, and hypercompact HII regions.

Although hypercompact HII regions have been known for over ten years, until recently only a very small number of these regions were known. Moreover, it is only in the past several years that these regions have come to be recognized as a distinct class of HII region and that attempts have been made to understand their place in the scheme of massive star formation.

Here we present a summary of the observational studies to date. We give special emphasis to radio continuum studies, which indicate density gradients within the ionized gas, and to radio spectral line studies, which show unusually broad recombination line profiles. Possible interpretations of these aspects of hypercompact HII regions are discussed, and their implications for the interpretation of hypercompact HII regions as an evolutionary stage in the high-mass star formation process.

We present atmospheric parameters, Li abundances, obtained from a detailed spectroscopic analysis, for a sample of stars with different evolutionary stages (turn–off, subgiant, giant stars) in the solar age cluster M67. Observations were carried out with high resolution ($R\sim47000$) at high S/N using the UVES${+}$FLAMES at VLT/UT2. From available photometry, computed synthetic spectra for the region around the Lithium line at 6707.78Å, we derived atmospheric parameters (T$_{\scriptsize\it eff}$, $\log g$, [Fe/H], $v\sin i$), A$_{Li}$ for each star, in order to better underst, the level of mixing, convective dilution of evolved stars in M67.

What is the origin of the numerous population of diffuse elliptical galaxies (dE)? These galaxies formed their stars several billion years ago and lost their gas. Though the stellar winds resulting from star formation and the interactions with the environment undoubtedly play a role, their respective role and details of this evolution are still debated.

In this presentation we will review the first 3D spectroscopic observations of a handful of dE galaxies. These data reveal complex kinematical structures, with embedded discs and counter rotating cores, and they open extremely promising perspectives for studying the history of the stellar population throughout these various features.

The presence of disks, which was already known from detailed image analysis, their complex kinematics, and the new constraints on the stellar population enforce the hypothesis of the evolutionary connection between dEs and disk galaxies.

Understanding deuterium fractionation is currently one of the greatest challenges in astrochemistry. In this contribution deuteration experiments of the series CH$_n^+$, n=2–5, in a low temperature 22-pole ion trap are used to systematically test a simple chemical rule predicting which molecular ion undergoes deuterium exchange in collisions with HD. CH$_4^+$ turns out to be a problem case, where prediction fails. The method of laser induced reaction (LIR) is used to determine the population ratio of the lowest ortho-to-para states of H$_2$D$^+$ relaxed in collisions with H$_2$. Preliminary results indicate that the ortho-to-para ratio of H$_2$D$^+$ is substantially reduced in para-H$_2$. This points at the important role of nuclear spin in deuterium fractionation, in particular at the destruction of ortho-H$_2$D$^+$ in collisions with ortho-H$_2$. More systematic LIR experiments are needed for a chemical model of deuterium fractionation including state-to-state modifications of the species involved.

Sloan Digital Sky Survey (SDSS) quasar spectroscopy is yielding a database of strong low-ionisation MgII absorbers over the redshift interval $0.36<z<2.28$ which is over two orders of magnitude larger than anything previously assembled. Hubble Space Telescope (HST) UV spectroscopy has been used to measure neutral hydrogen column densities for a small subset of them. These data empirically show that MgII absorbers with rest equivalent widths $W^{\lambda2796}_0 \ge 0.6$ Å have a mean neutral hydrogen column density that is roughly constant at $N(HI) \approx 4\times10^{20}$ atoms cm$^{-2}$, with individual systems lying in the damped Ly$\alpha$ (DLA) and sub-DLA regimes. Since the MgII doublets generally exhibit saturation, the $W^{\lambda2796}_0$ values are an indication of the absorbers' velocity spreads. Thus, we can study neutral-gas-phase metallicities as a function of kinematics by forming SDSS composite spectra and measuring weak unsaturated metal lines that form in neutral gas (e.g., CrII, FeII, MnII, SiII, ZnII) as a function of $W^{\lambda2796}_0$. We use this method on SDSS composite spectra to show how metallicity and kinematics are positively correlated for large-$N(HI)$ absorbers, including trends related to dust depletion and the enhancement of $\alpha$-elements. We also discuss the need to account for selection effects in DLA surveys, and we make inferences about models for DLA absorption and their contribution to cosmic star formation.

Commission 10 aims at the study of various forms of solar activity, including networks, plages, pores, spots, fibrils, surges, jets, filaments/prominences, coronal loops, flares, coronal mass ejections (CMEs), solar cycle, microflares, nanoflares, coronal heating etc., which are all manifestation of the interplay of magnetic fields and solar plasma. Increasingly important is the study of solar activities as sources of various disturbances in the interplanetary space and near-Earth “space weather”.

Over the past three years a major component of research on the active Sun has involved data from the RHESSI spacecraft. This review starts with an update on current and planned solar observations from spacecraft. The discussion of solar flares gives emphasis to new results from RHESSI, along with updates on other aspects of flares. Recent progress on two theoretical concepts, magnetic reconnection and magnetic helicity is then summarized, followed by discussions of coronal loops and heating, the magnetic carpet and filaments. The final topic discussed is coronal mass ejections and space weather.

The discussions on each topic is relatively brief, and intended as an outline to put the extensive list of references in context.

The review was prepared jointly by the members of the Organizing Committee, and the names of the primary contributors to the various sections are indicated in parentheses.

The absorption lines seen in the spectra of high redshift QSOs are important tools for studying the early evolution of galaxies and intergalactic medium. In this presentation I briefly review various available observations, our understanding of different types of absorption systems, and highlight some of the issues that can be addressed with ELTs.

Orbit determination for Near-Earth Asteroids presents unique technical challenges due to the imperative of early detection and careful assessment of the risk posed by specific Earth close approaches. This article presents a case study of asteroid 99942 Apophis, a 300-400 meter object that, for a short period in December 2004, held an impact probability of more than 2% in 2029. Now, with an orbit based on radar ranging and more than a year of optical observations, we can confidently say that it will pass safely by the Earth in 2029, although at a distance of only about six Earth radii from the geocenter. However, the extremely close nature of this encounter acts to obscure the trajectory in subsequent years, when resonant returns to the vicinity of the Earth are possible. In particular, an impact possibility in the year 2036 has a roughly 5% probability of persisting through the very favorable 2013 radar and optical observing apparition. In the event that the 2036 potential impact has not been eliminated by 2013, a precise characterization of the Yarkovsky accelerations acting on the asteroid may become an important part of the orbit estimation and impact prediction problem. Even so, the sixteen years available to effect a deflection from 2013 until 2029, after which the problem would become intractable, are sufficient to respond to the threat should a deflection effort become warranted.

The search for extrasolar planets is nowadays one of the most promising science drivers in Astronomy. The radial velocity technique proved to be successful in planet hunting, harvesting more than a hundred planets to date. In these last recent years, the transit method has come to fruition, with the detection of seven Jupiter-mass extrasolar transiting planets in close-in orbits (${<}0.05$ AU). Currently, the radius of planets can only be determined from transiting planets, representing the principal motivation and strength of this technique. The MPIA is presently building the Large Area Imager (LAIWO) for the 1m telescope in the Wise Observatory, Israel. LAIWO will have a field of view of one square degree. An intensive search for extra-solar planets will be performed with the 1m Wise telescope, together with the 1.2m MONET telescope in Texas. We will monitor three fields at a given time during three years and more than 200 nights per year. We expect several dozens of extra-solar planets.

I review recent developments in the field of radio observations of ultracompact H II (UCHII) regions that have appeared in the literature since the last major review (Churchwell 2002). The morphology of UCHII regions continues to be a topic of research and recent studies of individual regions of star formation suggest modifications with respect to the results obtained from galactic plane surveys. I also briefly touch upon the question of the density structure of UCHII regions. Finally, I will also discuss the evidence of time variability in UCHII regions, and present examples of objects that are expanding, varying in flux density, or moving in the sky.

The star formation, mass assembly and chemical enrichment histories of galaxies, and their present distributions of dark matter, remain encoded in their stellar populations. Distinguishing the actual distribution functions of stellar age, metallicity and kinematics at several locations in a range of galaxies, sampling across Hubble types and representative environments, is the information required for a robust description of galaxy histories. Achieving this requires large aperture, to provide the sensitivity to reach a range of environs and Hubble types beyond the Local Group, to provide high spatial resolution, since the fields are crowded, and preferably with optical performance since age-sensitivity is greatest near the main-sequence turn-off, and metallicity-sensitivity for these warm stars is greatest in the optical.

We present stellar parameters, Li abundances for 21 stars of the young ($\sim$50 Myears) AB Dor association, based on high-resolution spectra obtained with FEROS at the ESO 1.52m telescope, the Coudé Spectrograph at the OPD 1.6m telescope. These results are part of an ongoing project for the determination of stellar parameters, abundances for a large sample of T Tauri, post-T Tauri stars in PMS associations identified on the Search for Associations Containing Young Stars survey. The sample consists of G, K, M stars counterparts of ROSAT bright sources.

Since we expect Li depletion for the K, M stars, but small Li depletion for the G stars, we can compare the upper values of Li abundances for these stars with the one of the Galactic disk interstellar mean, at the same time provide constrains for the study of Li depletion on a chemically homogeneous high metallicity sample.

We review progress in the area of the modelling of shocks in molecular clouds. In particular, we consider what has been learnt about shock structure evolution in situations where the steady-state assumption is no longer valid. We discuss the interpretation of the observed water abundance from SWAS, Odin, and ISO. We also consider the erosion of grains in shocks as well as the effect of the presence of grains on shock structure.

We report 320 to 1020nm disk-averaged Earth reflectance spectra obtained from Moon's Earthshine observations with the EMMI spectrograph on the NTT at ESO La Silla (Chile). The spectral signatures of Earth atmosphere and ground vegetation are observed. A vegetation red-edge of up to 9% is observed on Europe and Africa and ${\approx}2%$ upon Pacific Ocean. The spectra also show that Earth is a blue planet when Rayleigh scattering dominates, or totally white when the cloud cover is large.

Mathematical modelling of meteoroid streams formation and evolution is a very fruitfull method for obtaining not only cosmogonical knowledges, but information about the stream up-to-date structure as well. In this review we consider advances of the method, and applications to meteoroid streams of different schemes of formation. We also discuss the part played by observations, and feedback between models and observations. Attention is also drawn to some unresolved problems and promising areas of application.

The recurrence time $T_{\rm C}$ of outbursts of the remarkable and unique system, the Rapid Burster (MXB 1730–335), observed by ASM/RXTE, is analyzed by the method of the O–C residuals. The variations of $T_{\rm C}$ are large and occur all the time, but generally they are not chaotic; the mean value of $T_{\rm C}$ is 160 days between the years 1996–2005 but a large shortening of $T_{\rm C}$, accompanied by a large decrease of the maximum intensity $I_{\rm max}$ and the relative energy RE (energy output) of most outbursts, occurred in this interval. The outbursts are found to display a correlation between RE and $I_{\rm max}$, but no correlation with the outburst duration. The observed behaviour is discussed in terms of the thermal instability of the accretion disk. A comparison of this prototype with other neutron star soft X-ray transients, like Aql X-1 and 4U 1608–52, helps us find the common links in the disk behaviour in such systems.

We compare the properties of dwarf galaxies in the Local Group with the simulated galaxies formed before reionization in a cosmological simulation of unprecedented spatial and mass resolution including radiative feedback effects. We find that a subset of the Local Group dwarfs, the dwarf Spheroidals, are remarkably similar to the simulated dwarf galaxies in all their properties already before reionization. Simulated and observed dwarf Spheroidal galaxies not only have similar properties but also follow the same scaling relations. Based on this similarity and on the observed ages of their dominant stellar populations we propose the hypothesis that Local Group dwarfs form in two different ways: (i) most dwarf Spheroidals are pristine fossils of the pre-reionization era and (ii) dwarf irregulars are more massive galaxies that formed most of their stars later, after reionization. There is also a group of “polluted fossils” with properties that are intermediate between these two main groups. We predict the existence of many more dwarf Spheroidals, fainter and with lower surface brightness than the observed population.

Commission 12 covers research on the internal structure and dynamics of the Sun, the “quiet” solar atmosphere, solar radiation and its variability, and the nature of relatively stable magnetic structures like sunspots, faculae and the magnetic network. There is considerable productive overlap with the other Commissions of Division II as investigations move progressively toward the fertile intellectual boundaries between traditional research disciplines. In large part, the solar magnetic field provides the linkage that connects these diverse themes. The same magnetic field that produces the more subtle variations of solar structure and radiative output over the 11 yr activity cycle is also implicated in rapid and often violent phenomena such as flares, coronal mass ejections, prominence eruptions, and episodes of sporadic magnetic reconnection.

The last three years have again brought significant progress in nearly all the research endeavors touched upon by the interests of Commission 12. The underlying causes for this success remain the same: sustained advances in computing capabilities coupled with diverse observations with increasing levels of spatial, temporal and spectral resolution. It is all but impossible to deal with these many advances here in anything except a cursory and selective fashion. Thankfully, the Living Reviews in Solar Physicsacute; has published several extensive reviews over the last two years that deal explicitly with issues relevant to the purview of Commission 12. The reader who is eager for a deeper and more complete understanding of some of these advances is directed to http://www.livingreviews.org for access to these articles.

We calculate in detail the expected properties of low redshift DLAs under the assumption that they arise in the gaseous disks of galaxies like those in the $z\approx 0$ population. A sample of 355 nearby galaxies were analysed, for which high quality H I 21-cm emission line maps are available as part of an extensive survey with the Westerbork telescope (WHISP). We find that expected luminosities, impact parameters between quasars and DLA host galaxies, and metal abundances are in good agreement with the observed properties of DLAs and DLA galaxies. The measured redshift number density of $z=0$ gas above the DLA limit is $dN/dz=0.045\pm 0.006$, which compared to higher $z$ measurements implies that there is no evolution in the co-moving density of DLAs along a line of sight between $z\sim 1.5$ and $z=0$, and a decrease of only a factor of two from $z\sim 4$ to the present time. We conclude that the local galaxy population can explain all properties of low redshift DLAs.