We investigate the secular resonances for massless small bodies and Earth-like planets in several planetary systems. We further compare the results with those of Solar System. For example, in the GJ 876 planetary system, we show that the secular resonances ν1 and ν2 (respectively, resulting from the inner and outer giant planets) can excite the eccentricities of the Earth-like planets with orbits 0.21≤ a <0.50 AU and eject them out of the system in a short timescale. However, in a dynamical sense, the potential zones for the existence of Earth-like planets are in the area 0.50≤ a ≤1.00 AU, and there exist all stable orbits last up to 105 yr with low eccentricities. For other systems, e.g., 47 UMa, we also show that the Habitable Zones for Earth-like planets are related to both secular resonances and mean motion resonances in the systems.

We report on the progress of our on-going campaign to monitor the evolution of the VLTP objects V4334 Sgr and V605 Aql, as well as the suspected (V)LTP object CK Vul. V4334 Sgr does not show signs of increased ionization compared to our previous observations in 2004. We obtained the first radio detection of V605 Aql, indicating a strong increase in radio flux since 1987. We also present the first radio detection of CK Vul and discuss the expansion of the material ejected during the 1670 event.

Longitudinal structure of the photospheric magnetic field over last tree solar cycles has been studied. The reconstruction of the longitudinal structure in the heliographic system rotating rigidly with Carrington rate was performed and compared with longitudinal distributions of random origin.

Changes in the double star database are highlighted, describing various methods of observation (both historically and those of the past few years) and their effectiveness in different regimes of separation space. The various niches for wide- and narrow-field work as they apply to double and multiple stars are examined and the different types of information which each can provide are described. Despite the significant growth of the double star database, much can still be done, such as finding lost pairs, filling in missing parameters so that observing programs can select all stars appropriate to their capabilities, or providing at least gross kinematic descriptions. After more than 20 years of successful work, speckle interferometry and conventional CCD astrometry have replaced filar micrometry and photography as preferred classical techniques. Indeed, most work in filar micrometry is now being done by amateurs. Work on pairs described as neglected in the last major WDS data release (2001) is given as a specific example. Finally, the continued need to publish data in classical double star parameters is also discussed.

Accurate measurements of emission line properties are crucial to understand the physics of the broad line region in quasars. This region consists of warm gas that is closest to the quasar central engine and has not been spatially resolved for almost all sources. We present here an analysis of optical and IR data for a large sample of quasars, covering the Hi Hβ spectral region in the redshift range 0 ≲ z ≲ 2.5. Spectra were interpreted within the framework of the the so-called “eigenvector 1” parameter space, which can be viewed as a tentative H-R diagram for quasars. We stress the lack of spectral evolution in the low ionization lines of quasars, with prominent Fe ii emission also at z ≳ 2. We also show how selection effects influence the ability to find quasars radiating at low Eddington ratio in flux-limited surveys. The quasar similarity at different redshift is probably due to the absence of super-Eddington radiators (at least within the caveats of black hole mass and Eddington ratio determination discussed in this paper) as well as to the limited Eddington ratio range within which quasars seem to radiate.

Observations give tight constraints on the temporal and spatial scales of particle heating in solar flares, and on the required efficiency. Electrons are accelerated into a quasi-thermal population of a few tens of keV. X- and γ-rays imply tails in electron and ion distributions reaching tens of MeV and above. Simple estimates indicate that all available electrons are accelerated at least once to moderate energies, pointing to an initial process resembling bulk heating rather than acceleration of a small or localized population. In the absence of effective collisions, wave-particle interactions are the prime candidate. Here we address the outstanding questions, (i) what process can heat the entire reconnecting plasma to the above energies, and (ii) what provides the free energy for wave-particle interactions? We propose a process in which initially the ions are heated and provide the free energy for electron heating and tail formation.

I review the current status of stellar population modelling, with particular emphasis on the treatment of the Thermally-Pulsing Asymptotic Giant Branch stellar phase. I discuss how much the physical properties of galaxies that are derived applying these models to real data, depend on the adopted model.

HI observations at sufficiently high spatial and velocity resolution have revealed a wealth of structures such as shells and bubbles in the ISM of late–type galaxies. These structures are filled with metal–enriched, coronal gas from SNe which, through overpressure, powers their expansion. Material swept up by these expanding shells can go “critical” and form subsequent (secondary or propagating) star formation. Shells that grow larger than the thickness of the gas layer will blow out of the disk, spilling enriched material into the halo (or in the case of violent starbursts, the Intergalactic Medium). We review what has been achieved to date and present some first results of a major project based on THINGS (The HI Nearby Galaxy Survey), which aims to extend studies of the ISM in galaxies to 34 nearby systems (<10 Mpc), all observed to the same exacting standards (resolution 6″ × 5 km s−1, or better; typical detection threshold of ~5 × 1019 atom cm−2).

Beginning in 2001, the Gemini Observatory began the development of an innovative and aggressive education and outreach programme at its southern hemisphere site in northern Chile. A principal focus of this effort is centered on local education and outreach to communities surrounding the observatory and its base facility in La Serena, Chile. Programmes are now established with local schools using two portable StarLab planetaria, an internet-based teacher exchange called StarTeachers and multiple partnerships with local educational institutions. Other elements include a CD-ROM-based virtual tour that allows students, teachers and the public to experience the observatory's sites in Chile and Hawaii. This virtual environment allows interaction using a variety of immersive scenarios such as a simulated observation using real data from Gemini. Pilot projects like “Live from Gemini” are currently being developed which use internet video-conferencing technologies to bring the observatory's facilities into classrooms at universities and remote institutions. Lessons learned from the implementation of these and other programmes will be introduced and the challenges of developing educational programming in a developing country will be shared.

We investigate the properties of non-local Reynolds stress models of turbulent convection in a spherical geometry. Regularity at the centre r=0 places constraints on the behaviour of 3rd order moments. Some of the down-gradient and algebraic closure models have inconsistent behaviour at r=0. A combination of down-gradient and algebraic closures gives a consistent prescription that can be used to model convection in stellar cores.

The stellar population models dramatically progressed with the arrival of large and complete libraries, ELODIE, CFLIB (=Indo-US) and MILES at a relatively high resolution. We show that the quality of the fits is not anymore limited by the size of the stellar libraries in a large range of ages (0.1 to 10 Gyr) and metallicities (−2 to +0.4 dex). The main limitations of the empirical stellar libraries are (i) the coverage of the parameter space (lack of hot stars of low metallicity), (ii) the precision and homogeneity of the atmospheric parameters and (iii) the non-resolution of individual element abundances (in particular [α/Fe]). Detailed abundances measurements in the large libraries, and usage of theoretical libraries are probably the next steps, and we show that a combination between an empirical (ELODIE) and a theoretical library (Coelho et al. 2005) immediately improves the modeling of (α-enhanced) globular clusters.

Many of our annual showers do not have active parent comets. In recent years, minor planets have been identified that move among the meteoroids streams. Some streams, such as the Quadrantids, Geminids, and Sextantids, are in such unusual orbits that the probability of a chance association is only of order 1 in 106. The streams identify those objects as dormant comet nuclei. Other streams, such as the Phoenicids and α-Capricornids are associated with minor planets that were found to be weakly active at their last perihelion passage. All the streams investigated so far are young, less than 2,000 years old, and can not have been created in the classical sense of meteoroids being ejected from the comet nucleus by water vapor drag. Instead, these (mostly) dormant comets lost fragments at some point in the past, which crumbled into meteoroid streams. Scars of such events are now identified on the surface of active Jupiter family comets 9P/Tempel 1 and 81P/Wild 2. Thus, the meteor showers on Earth bear witness to what is the dominant mass-loss mechanism of comets in the inner solar system, a process that can account for much of the zodiacal cloud dust and the zodiacal dust bands.

During the rising phase of the August 30, 2002 X1.5 flare a short pulse with a total duration of 8 seconds was observed. Its background-subtracted radio spectrum ranges only from 5 to 12 GHz with a maximum flux density of approximately 900 s.f.u. at 7 GHz and a steep optically thin spectral index α ≃ 8. Maximum degree of polarization at 7 GHz is around 5%. The hard X-ray pulse emission above the background in the range of 30–150 keV observed by RHESSI is coincident in time with the microwave observation. Hard X-ray images reveal very compact (∼ 10″) footpoint sources. Below 30 keV, a thermal source is observed.

We have examined the behavior of a number of bolides in Earth's atmosphere from the standpoint of recent entry modeling techniques. The entry modeling has been carried out including a triggered progressive fragmentation model (TPFM) which maintains a maximum drag orientation for the fragments in either the collective or a non-collective wake limit during entry (ReVelle 2004). Specifically in this paper, we have proposed a new method of estimating the terminal bolide mass and have compared it against the corresponding single-body mass loss prediction. A new expression for the terminal mass is proposed that corrects the mass of the body for the changing mass to area ratio during the fragmentation process. As a result of this new work we have found two very interesting features that correspond very closely to those found from a direct analysis of the observational data. These include an instantaneous mass that closely resembles that directly observed and an ablation coefficient behavior that also strongly resembles meteor observations (such as those found recently by Ceplecha & ReVelle 2005). During fragmentation, the apparent ablation coefficient has now been shown to decrease dramatically approaching the intrinsic ablation coefficient proposed by Ceplecha & ReVelle (2005). In our modeling we have assumed a breakup into equal size fragments that are consistently and progressively multiples of two of the original unbroken leading piece. Had we assumed a multitude of many much smaller pieces that made up the totality of the original body, our predicted ablation coefficient would indeed have approached the very small intrinsic ablation parameter values predicted by Ceplecha and ReVelle. This is especially evident in the case of Sumava, but is also true in a number of other cases as well. The bolides whose properties have been modeled using our detailed entry code including a prediction of the panchromatic luminosity consist of the 1965 Revelstoke meteorite fall (Folinsbee 1967; Carr 1970; Shoemaker 1983), the 1974 Sumava fireball and the 1991 Benesov fireball as presented in Borovička & Spurný (1996) and in Borovička et al. (1998), the Tagish Lake meteorite fall of January 8, 2000 (Brown et al. 2002), the March 9, 2002 Park Forest meteorite fall (Brown et al. 2004), the June 6, 2002 Mediterranean (Crete) bolide as presented in Brown et al. (2002) and finally the September 4, 2004 Antarctic bolide respectively (Klekociuk et al. 2005). A self-consistent assessment of the detailed properties of each of the fireballs was made using all available information for each event. In the future, more reliable estimates of all of the necessary source parameters (including their overall degree of bulk porosity) will be made if all channels of information are reliably retrieved for bolide events (channels such as acoustic-gravity waves and specifically its infrasound emission, seismic waves, satellite optical and IR data, ground-based spectroscopy, ground-based photometry and radiometry, VLF radiation, meteorite fragment recovery, etc.).

It was performed a study of the North-South asymmetry of the magnetic field distribution by comparison of the temporal behavior of long and short term variabilities of the photospheric field at the same latitudes in opposit hemispheres using WSO data sets covered the interval from 1976 to 2005.

I present a brief review of current work on dwarf galaxy age-metallicity relationships.

We introduce an extended 3D numerical simulation study of Reynolds stress models of stellar convection and probe fluxes as well as mean temperature gradient profiles.

A review of the spectroscopic properties of post-AGB stars is presented.

Due to improvements in technology (interferometers, precision radial-velocity techniques, etc.), the traditional separation/period regimes of “wide” and “close” binaries are witnessing increasing overlap. This is expected to lead to increasing confusion in component identification, since different observing techniques adopted their own rules for designation of these components. A quick overview will be given of the Washington Multiplicity Catalog, an effort to create a common nomenclature scheme for all types of stellar and sub-stellar companions.

We present and discuss in this work the motivations, goals and strategies adopted for its creation and launch of the e-journal Latin-American Journal of Astronomy Education (RELEA). We identify and present the difficulties encountered for the achievement of the proposed objectives and operational issues in this period, together with the adopted solutions (refereeing procedure, periodicity, etc.).