Angular momentum transport plays an important role in mass transfer systems, and can significantly spin up an accreting star. When the accretor is a white dwarf (WD) on its way to becoming a Type Ia supernova (SN Ia), the spin up of the WD can have significant consequences for the appearance of the progenitor, the characteristics of the explosion and its aftermath, the geometry of the supernova remnant, and for single-degenerate models, the appearance of the donor star post-explosion. These consequences can be “game changers”, altering results that have long been taken for granted. We discuss key features of our spin-up/spin-down models and their implications. We relate our models to work still needed to address the difficult physical issues related to angular momentum transport and its effects on the properties and appearance of Type Ia supernova progenitors.

A general method, which allows us to derive explicit expressions for the differential operator of stationary quasi-monochromatic polarized radiative transfer equation in Euclidean space, with piecewise homogeneous real part of the effective refractive index, is applied to ellipsoidal, oblate spheroidal, prolate spheroidal and elliptic conical coordinate systems.

Several progenitor scenarios have been suggested for Type Ia supernovae. Here we discuss the consequences for the explosion mechanism and for observables of some of them, which are explored by means of multi-dimensional hydrodynamic and radiation transfer simulations. While the observables predicted from delayed detonations of Chandrasekhar-mass white dwarfs agree reasonably well with the data, the corresponding progenitor systems may be too rare to account for the observed rate of Type Ia supernovae. Several alternatives are investigated of which violent mergers of two white dwarfs and, perhaps, double detonations of sub-Chandrasekhar mass white dwarfs hold promise for reproducing the observables of normal Type Ia supernovae.

We discuss the origin and evolution of low mass contact binaries with Porb shorter than 0.3 d that have properties somewhat different from the rest of the contact binaries. A comparison of an evolutionary model set with observations shows that both components are on the main sequence, the age of the binaries is at least several Gyr, while the contact phase lasts only less than 1 Gyr.

We use binary population synthesis to study the main proposed channels leading to Type Ia supernovae, the single degenerate channel (SD) and double degenerate channel (DD). For this purpose, we discuss the progenitor evolution and the influence of the common envelope efficiency, αce, on the rate of the different channels. Our study demonstrates the large αce-dependence of both channels, especially for the SD channel.

Magnetic fields appear ubiquitous throughout the envelopes of evolved stars. However, their origin and role in the formation of planetary nebulae is still unclear. As observations of magnetic fields are complicated and time consuming, the observed samples of AGB and post-AGB stars and planetary nebulae are still small. Still, magnetic energy seems to dominate the energy budget out to a distance of several tens of AU from the central star and the field morphology often appears to be well ordered. A short summary is given of the current observations and the potential of new instruments such as ALMA is discussed.

Our photometric CCD observations of the short-period cataclysmic star AR UMa in 2008 during its low state revealed light variability with a bigger period (by around 10%) and considerably smaller amplitudes than the previous ones. The light curve had a single-wave shape, opposite to the previously observed low states which revealed doubled-humped shape.

We present long-term observations of magnetic cataclysmic variables AM Her, AN UMa, AR UMa, DP Leo, and V1309 Ori obtained with the ROTSEIIId telescope. All data have been analysed and preliminary results indicate periods of 170 days, 217 days, and 180 days for AM Her, AN UMa, and AR UMa, respectively.

We construct a detailed model for the IR dust emission from the PN IC 418. We succeed to reproduce the emission from 2 to 200 μm. We can determine the amount of emitting dust as well as its composition, and compare to the depletion of elements determined for the photoionized region.

The derived physical properties of the known transiting extrasolar planetary systems come from a variety of sources, and are calculated using a range of different methods so are not always directly comparable. I present a catalogue of the physical properties of 58 transiting extrasolar planet and brown dwarf systems which have been measured using homogeneous methods, resulting in quantities which are internally consistent and well-suited to detailed statistical study. The main results for each object, plus a critical compilation of literature values for all known systems, have been placed in an online catalogue. TEPCat can be found at http://www.astro.keele.ac.uk/~jkt/tepcat/

The conference organizers are grateful to everyone who came, from all parts of the world, to share this experience with us. There were one hundred and seventy-seven participants from thirty-one countries. We thank the speakers, session chairs, distinguished panelists, the SOC members, the LOC members led by Theo Pribulla and Laco Hric, and Aleš Kucera, Director of the Astronomical Institute of the Slovak Academy of Sciences. Special thanks go to Richard Komžík for ensuring the smooth operation of the computer and audio-visual support for the conference.

The recurrent nova RS Oph is a long period (~455 days) binary system consisting of a hot white dwarf with mass close to the Chandrasekhar limit and an M-type giant secondary. Here we present the results of photometric observations of this nova which were made during recent years with the telescopes of the Sternberg Astronomical Institute in Crimea.

We present preliminary results obtained from the analysis of very deep echelle spectra of a dozen planetary nebulae with [WC] or weak emission lines (wels) central stars. The computed abundance discrepancy factors (ADFs) are moderate, with values lower than 4. In principle, no evidence of the H-poor metal enriched inclusions proposed by Liu et al. (2000) have been found. However, a detailed analysis of the data is in progress.

Short review of our 36-year Cyg X-1 study using multi-technique methods and based on our optical photometric, high-resolution spectral and spectropolarimetrical observations.

Supersoft X-ray fluxes in early-type galaxies provide an excellent test for Type Ia supernovae (SNe Ia) progenitors: the double degenerate (DD) scenario is believed to produce no supersoft sources (SSSs) except just before the SN Ia explosion, while the single degenerate (SD) scenario produces SSSs in some phases of the symbiotic channel. Recent observations of the supersoft X-ray flux of early-type galaxies show a remarkable agreement with theoretical predictions of the SD scenario, which thus turns out to be a strong support for the SD scenario, despite the original observations aimed at the opposite conclusion. Here I explain why X-ray fluxes are so weak in early-type galaxies. (1) Candidate binaries in the SD scenario become SSSs only during a short time on their way to SNe Ia explosions, because they spend a large part of their lifetime in a wind phase. (2) During the SSS phase, symbiotic stars emit very weak supersoft X-ray fluxes even if the WD is very massive. It should be emphasized that supersoft X-ray symbiotic stars are very rare and we need more observations to understand their nature.

The orbital angular momenta OAM (J) of detached binaries (including both cool and hot binaries) were estimated and nine subgroups were formed according to their OAM (J) distribution. The mean kinematical ages of all subgroups have been estimated by using their space velocity distributions and, thus, the age dependent variations of the mean OAM (J), orbital period (P), and total mass (M) of all subgroups were investigated. It was discovered that: i) The orbital period of detached binaries with radiative components decrease very slowly during the main sequence (MS) evolution. It is interesting that the large amount of mass loss is almost balanced by the OAM loss, and not much change in the orbital periods is observed. ii) The nuclear evolution of radiative components beyond the MS initiates the increase of the periods until the components have convective upper layers, i.e. until they become later than F5 IV, and the system becomes a cool binary with sub-giant or giant components. iii) The large co-rotating distance of the magnetically-driven wind in cool binaries (CAB) carries out a large amount of OAM and then the periods of such binaries decrease significantly, and the orbits shrink until another effect such as mass transfer dominates the period changes.

The nature and timescales behind the growth of the white dwarf toward the Chandrasekhar mass are not known. The two leading competing scenarios for Type Ia supernovae (SNe Ia) are accretion from a companion [single degenerate (SD)] or merger with another white dwarf [double degenerate (DD)]. Measurement of the SNe Ia delay time distribution could distinguish between these scenarios. Possibly both channels operate, on short (SD) and long (DD) time scales. A supernova search in parallel with our Cluster Lensing And Supernova survey with Hubble extends the Hubble diagram of SNe Ia to z > 1.5, probing progenitor evolution and testing the constancy of dark energy (DE) with time. We use HST ACS to detect SNe Ia at 1 < z < 1.5 and WFC3 to find SNe Ia at 1.5 < z < 2.5, thus providing constraints for the variation in the DE equation of state. This redshift epoch provides the unique chance to test SNe Ia distance measurements for the deleterious effects of evolution independent of our ignorance of dark energy. Our program provides the first measurement of the SNe Ia rate at z ~ 2.

We present narrow-band optical and near-IR images, and high-resolution long-slit spectra of the planetary nebula Hu 1-2 that allow us to make a detailed description of its unusual morphology and internal kinematics. The data also reveal that the ansae of Hu 1-2 probably represent bow-shocks associated to high velocity outflows that are irradiated from the central star.

We analyze the results of our IR photometric monitoring of T CrB during 1987-2003 and describe the ellipsoidal variability of the Roche lobe filling cool component. We obtain limits to the binary inclination of i ∈ [50,60] deg and binary mass ratio q ∈ [0.4,2] (90 per cent confidence). The mass of the hot component is therefore 1.3-3 M⊙. If the hot component of T CrB is a white dwarf, its mass will be near the Chandrasekhar limit.