On the long road from dust to planets there are planetesimals. We review and criticize proposed mechanisms for planetesimal formation, and point out topics for future work.

We present the first detailed three-dimensional hydrodynamic implicit large eddy simulations of turbulent convection for carbon burning. The simulations start with an initial radial profile mapped from a carbon burning shell within a 15 M⊙ stellar evolution model. We considered 4 resolutions from 1283 to 10243 zones. These simulations confirm that convective boundary mixing (CBM) occurs via turbulent entrainment as in the case of oxygen burning. The expansion of the boundary into the surrounding stable region and the entrainment rate are smaller at the bottom boundary because it is stiffer than the upper boundary. The results of this and similar studies call for improved CBM prescriptions in 1D stellar evolution models.

A survey for the molecules C2H and HC3N in a variety of interstellar clouds has been completed. Both molecules are very widespread, in cold dark clouds as well as in hot clouds. C2H emission has been mapped in L1534. In cold clouds the fractional abundance X(C2H) is found to be 2-6×10−9. The ratio of abundances X(C2H)/X(HC3N) falls in the range 6-10, consistent with some gas-phase reaction schemes for these molecules.

Current knowledge of the chemical nature of WR stars determined from UV, optical and IR spectral analyses, is reviewed. By number, the H/He ratio is low in most WN stars: 10 ≥ H/He ≥ 0.4 for WNL stars; 3.0 ≥ H/He ≥ 0.0 for WNE stars with most having near zero H-abundances. The C/N ratio in WN stars lies in the range 1–6 × 10−2, whilst N/He ∼10−4 − 4 × 10−3. These abundances for WN stars are broadly consistent with equilibrium CNO-burning products. In WC stars H/He=0 whilst C/He ∼ 0.1 − 0.7 with some evidence for increasing values from WC7 → WC4. N is highly deficient in WC stars, with C/N≥ 60, and for HD 165763 O/C ≤ 0.2 is deduced. In γ Velorum (WC8+O9), IR spectra give a value of Ne/He = 1.0×10-3 (about twice solar). Thus WC abundances are broadly consistent with He-burning products, although the Ne abundance appears lower than predicted. WO stars show C/He ∼ 0.2 − 0.7, and O/He ∼ 0.03 − 0.1, revealing both He-burning and α-capture products. Ring nebulae around several WN stars shown enhanced He and N, consistent with mass loss enrichment expectations from their chemically evolved central stars. Enhanced He (and probably N) is also seen in the atmospheres of several LBVs, OBN and Of stars - potential precursors of, at least, some WN subtypes.

Before reviewing the radio properties of active spiral galaxies it is appropriate, as well as instructive, to think about a working definition of an active galaxy. This may seem a trivial point when we consider classes of objects like Seyfert galaxies or radio galaxies but this is much less so when we inspect the nearby systems. In a sample of nearby galaxies one is likely to encounter much more milder forms of activity than that known from studies of more distant galaxies. This is, of course, due to the fact that the latter have been selectively taken from a much larger reservoir of objects. (Although this may seem a disadvantage from an observational point of view, there are some clear advantages as well. Firstly, we can obtain a much better linear resolution once we have been able to isolate the active nearby galaxies and, secondly, we eventually may hope to learn more about the physical situation that existed prior to the onset of the active period and how the surrounding medium reacts to the activity.)

The solar granulation has been simulated by numerical solution of the multidimensional, time-dependent, nonlinear Navier-Stokes equations applied to the solar atmosphere. Granules may be explained as buoyantly rising bubbles created at the level where T = 8000 K, and which have collapsed into vortex rings. The calculation is in quantitative agreement with observations and has a number of implications for solar physics and convection theory.

Evolution in the merger rate as a function of redshift is in principle the key observable testing hierarchical models for the formation and evolution of galaxies. However, in practice, direct measurement of this quantity has proven difficult. In this opening review I outline the current best estimates for the merger rate as a function of cosmic epoch, focusing mostly upon recent advances made possible by deep ground-based redshift surveys and morphological studies undertaken with HST. I argue that a marriage of these techniques, in an attempt to determine the space density of mergers amongst the abundant morphologically peculiar population at high redshifts, is probably the most promising currently-available avenue for determining the prevalence of mergers at high redshifts. However, resolved kinematical studies, which seem set to become available in the next few years, are probably the best hope for a definitive determination of the space density of mergers at high redshifts.

The recent discovery of a gravitational wave from the merging of two black holes of about 30 solar masses each challenges our incomplete understanding of massive stars and their evolution. Critical ingredients comprise mass-loss, rotation, magnetic fields, internal mixing, and mass transfer in close binary systems. The imperfect knowledge of these factors implies large uncertainties for models of stellar populations and their feedback. In this contribution we summarize our empirical studies of Wolf-Rayet populations at different metallicities by means of modern non-LTE stellar atmosphere models, and confront these results with the predictions of stellar evolution models. At the metallicity of our Galaxy, stellar winds are probably too strong to leave remnant masses as high as ~30 M⊙, but given the still poor agreement between evolutionary tracks and observation even this conclusion is debatable. At the low metallicity of the Small Magellanic Cloud, all WN stars which are (at least now) single are consistent with evolving quasi-homogeneously. O and B-type stars, in contrast, seem to comply with standard evolutionary models without strong internal mixing. Close binaries which avoided early merging could evolve quasi-homogeneously and lead to close compact remnants of relatively high masses that merge within a Hubble time.

Coronal structure and coronal heating are intimately related in magnetically active stars. Coronal structure is commonly inferred from radio interferometry and from eclipse and rotational modulation studies. We discuss to what extent flares may be responsible for coronal structure and global observable properties in magnetically active stars.

There is a long-standing mystery about the formation of the jets and lobes from AGN's. In the present paper, a “gravo-magnetodynamic” picture is proposed for the production of the jets and lobes from AGN's: The primordial large scale magnetic field, which is squeezed by the gravitational contraction of the material to the central object, serves in driving out the spinning jets in bipolar directions, and at the same time, serves as a drain extracting angular momentum of the disk material, enhancing the accretion and therefore enhancing the liberation of the gravitational energy at the center.

The ESA astrometric mission Gaia will be able to put to test General Relativity thanks to differential astrometric measurements. The differential experiment, GAREX, implemented in the form of repeated Eddington-like measurement, aims at measuring the quadrupole light bending due to an oblate planet by comparing the evolution of relative distances in stellar fields in the vicinity of it. Simulations which utilize (i) selected fields extracted from the GSCII data base, (ii) a realistic error model as function of the star's magnitude and distance from Jupiter's edge, show the real best scenarios and how to improve the Gaia ability to detect this relativistic effect.

Arabic star names are well known in two areas: in the Orient itself, i.e. in the Arabic-Islamic civilization, and in the West where many of them were adopted since mediaeval times and continued to be used until today.

The complex known in modern Western astronomy as “Arabic star names” is the result of a historical development of almost exactly one thousand years. In mediaeval times, those names were introduced into Western use by Latin translations of Arabic astronomical and astrological works. Afterwards, since Humanist and Renaissance times, and until this present century, Western astronomers used to pick up more “Arabic” names from philological studies of orientalists who tried to describe and explain the stellar nomenclature of the Arabs and other Oriental peoples. As outstanding examples, I mention the studies of Joseph Scaliger and his follower Hugo Grotius (both printed in 1600) whose nomenclature was borrowed by Johannes Bayer into his star atlas Uranometria of 1603; Thomas Hyde’s commentary to his edition of Ulugh Bēg’s star catalogue (Oxford, 1665) from which Giuseppe Piazzi borrowed a great number of names into the second edition of his Palermo Catalogue, 1814; German studies by F.W.V. Lach (1796) and Ludwig Ideler (1809) which were used by continental astronomers such as J.E.Bode and many others; and still the book on star names by R.H. Allen (1899) from which several new names appear in astronomical books and atlases of our times.

We present results from a high resolution study of six Li-depleted halo dwarfs. These stars exhibit Lithium abundances more than 0.5 dex below the Spite Plateau. The study is comprised of two parts: 1) a detailed abundance analysis covering many light, alpha, Fe-peak and neutron capture elements and 2) a study of rotational line broadening. We find that there are no common abundance anomalies, other than the Lithium depletion, that distinguish these stars from the Li-normal population. Four of the six stars however, show evidence of abnormally high projected rotation velocities. These findings support a non-standard depletion mechanism in Li-depleted halo stars, and emphasize their necessary exclusion from future studies of the Spite Plateau.

Although the subject of this meeting is triggered star formation in a turbulent interstellar medium, it remains unsettled what role magnetic fields play in the star formation process. This paper briefly reviews star formation model predictions for the ratio of mass to magnetic flux, describes how Zeeman observations can test these predictions, describes new results – an extensive OH Zeeman survey of dark cloud cores with the Arecibo telescope, and discusses the implications. Conclusions are that the new data support and extend the conclusions based on the older observational results – that observational data on magnetic fields in molecular clouds are consistent with the strong magnetic field model of star formation. In addition, the observational data on magnetic field strengths in the interstellar medium strongly suggest that molecular clouds must form primarily by accumulation of matter along field lines. Finally, a future observational project is described that could definitively test the ambipolar diffusion model for the formation of cores and hence of stars.

The Atacama Large Millimeter/submillimeter Array (ALMA) was used to obtain measurements of spatially and spectrally resolved CH3OH emission from comet C/2012 K1 (PanSTARRS) on 28-29 June 2014. Detection of 12-14 emission lines of CH3OH on each day permitted the derivation of spatially-resolved rotational temperature profiles (averaged along the line of sight), for the innermost 5000 km of the coma. On each day, the CH3OH distribution was centrally peaked and approximately consistent with spherically symmetric, uniform outflow. The azimuthally-averaged CH3OH rotational temperature (Trot) as a function of sky-projected nucleocentric distance (ρ), fell by about 40 K between ρ= 0 and 2500 km on 28 June, whereas on 29 June, Trot fell by about 50 K between ρ =0 km and 1500 km. A remarkable (~50 K) rise in Trot at ρ = 1500-2500 km on 29 June was not present on 28 June. The observed variations in CH3OH rotational temperature are interpreted primarily as a result of variations in the coma kinetic temperature due to adiabatic cooling, and heating through Solar irradiation, but collisional and radiative non-LTE excitation processes also play a role.

The orbital modulation of the X-ray and radio emission of Cyg X-3 was studied using monitoring data from CGRO/BATSE, RXTE/ASM, GBI and the Ryle telescope as well as recent INTEGRAL observations. The depth of the X-ray modulation was found to be the same at X-ray energies ranging from 1.5 up to at least 20 keV, but the shape of the lightcurves changes gradually with energy. No modulation was found in radio.

The variability of solar radiance over a solar cycle is thought to be a delicate balance between the radiative deficit of sunspots and the extra contribution of plage and network regions. Although the net effect is tiny, it must imply structural and thermal changes in the Sun or in partial layers of it as an unavoidable consequence of the virial theorem. Using the virial theorem for continua including the magnetic field it is shown, how solar radiance variability might be connected to a deeply seated flux-tube dynamo and how this connection is established on a hydrodynamical time-scale.To search for other articles by the author(s) go to: http://adsabs.harvard.edu/abstract_service.html

The International Heliophysical Year (IHY) in 2007 & 2008 will celebrate the 50th anniversary of the International Geophysical Year (IGY) and, following its tradition of international research collaboration, will focus on the cross-disciplinary studies of universal processes in the heliosphere.

The main goal of the IHY Education and Outreach Programme is to create more global access to exemplary resources in space and Earth science education and public outreach. By taking advantage of the IHY organization with representatives in every nation and in the partnership with the United Nations Basic Space Science Initiative (UNBSSI), we aim to promote new international partnerships. Our goal is to assist in increasing the visibility and accessibility of exemplary programmes and in the identification of formal or informal educational products that would be beneficial to improve space and Earth science knowledge in a given country; leaving a legacy of enhanced global access to resources and of world-wide connectivity between those engaged in education and public outreach efforts that are related to IHY science.

Here we describe how to participate in the IHY Education and Outreach Programme and the benefits in doing so. Emphasis will be given to the role played by developing countries; not only in selecting useful resources and helping in their translation and adaptation, but also in providing different approaches and techniques in teaching.

Observations of the diffuse X-ray background in the B and C bands (130-188 eV and 160-284 eV, respectively) provide convincing evidence for the existence of high-temperature interstellar gas. Since the opacity of normal interstellar material is very high, we must assume that the soft X-ray flux observed in the galactic plane originates within a few hundred parsecs of the Sun. The intensity and B/C ratio of this low-latitude flux can be provided by emission from an equilibrium plasma with normal abundances, T = 106.0 K, and 0.0019 cm-6 pc emission measure. More sophisticated nonequilibrium models of material heated by a supernova blast wave would reduce the required emission measure somewhat, but not by so much as a factor of two. Arbitrarily limiting the pressure to 104 cm-3 K gives a maximum density of 0.005 cm-3 and a minimum radius for the emitting region of 75 pc. This fits in well with UV interstellar absorption measurements which indicate that the ISM is very deficient in neutral hydrogen out to ~100 pc from the Sun.

The constancy of the observed B/C ratio implies that there are less than 5x1019 cm-2 variations in any cooler material lying between us and the bulk of the emission. This is consistent with the much smaller column densities of neutral or partially ionized material detected in the solar neighborhood through UV absorption measurements, but the organization of the cooler gas and its interaction with the coronal material require further investigation.

X-ray intensities at high latitudes are larger than those in the plane by as much as a factor of three. The fluctuations show a global anti-correlation with H I column density which suggests that they might be caused by variations in the transmission of X-rays from an extragalactic source, such as a galactic halo or corona. Such models are very difficult to reconcile quantitatively with existing H I measurements, however, and it seems more likely that the bulk of the high-latitude excess is produced by an extension of the unabsorbed interstellar emission in those directions with the remaining fluctuations produced by a combination of absorption and displacement by embedded cooler material, or possibly by transmission of flux from a hot halo.

While it would be most interesting to resolve this point because of its impact on the nature of the galactic halo and the high-latitude H I distribution, it does not greatly affect the amount of hot gas which apparently exists in the solar neighborhood: an isotropic emitting region with only the emission measure required by the average intensity near the galactic plane would account for about two-thirds of the integrated B and C band flux observed at the Earth. The total energy flux is ~1x10-6 ergs cm-2 s-1 if we assume a thermal equilibrium spectrum.

We summarize here some of the distribution properties of CO clouds in our galaxy as determined by observation and by computer simulations of these observations. The simulations adequately account for the number of clouds, their spatial separation, and their relative velocities with respect to one another. The principal shortcoming of the axisymmetric simulations is their failure to describe adequately the clustering of clouds seen in the velocity-longitude domain.