The Scattered Disk Population and the Oort Cloud

The trans-Neptunian belt has been subject to a strong depletion that has reduced its primordial population by a factor of one hundred over the solar system's age. One by-product of such a depletion process is the existence of a scattered disk population in transit from the belt to other places, such as the Jupiter zone, the Oort cloud or interstellar space. We have integrated the orbits of the scattered disk objects (SDOs) so far discovered by 2500 Myr to study their dynamical time scales and the probability of falling in each of the end states mentioned above, paying special attention to their contribution to the Oort cloud. We found that their dynamical half-time is close to 2.5 Gyr and that about one third of the SDOs end up in the Oort cloud.     

Colour Properties and Trends in Trans-Neptunian Objects

One of the most puzzling features of the Kuiper Belt, which has been confirmedby numerous surveys, is the optical colour diversity that seems to prevail among the observed TNOs. TNOs and Centaurs have surfaces showing dramaticallydifferent colours and spectral reflectances, from neutral to very red. With therelatively few visible-NIR colour datasets available, the colour diversity seemsalso to extend to the near infrared wavelengths. Relevant statistical analyses havebeen performed and several studies have pointed out strong correlations betweenoptical colours and some orbital parameters (i, e, q) for the Classical KuiperBelt objects. On the other hand, no clear trend is obvious for Plutinos, Scatteredobjects or Centaurs. Another important result is the absence of correlation of colourswith size or heliocentric distance for any of the populations of outer Solar Systemobjects. The strong colour anisotropy found is important because it is a diagnosticof some physical effects processing the surfaces of TNOs and/or some possiblecomposition diversity. In this paper, we will review the current knowledge of thecolour properties of TNOs, describe the observed colour distribution within theEdgeworth–Kuiper belt, and address the problem of their possible origin.     

Structural Evolution of the Eastern Margin of Eurasia in Late Mesozoic and Cenozoic

This paper features the structural evolution of the eastern margin of Eurasia in Late Mesozoic and Cenozoic.It is characterized by three stages of development: the riftogenic stage (Jurassic-Early Cretaceous), the platform stage (Late Cretaceous) and the neotectonic one (Paleogene-Quarternary). The boundaries between these stages are distinctly fixed by the geological time limits of planetary range. It is demonstrated that the riftogenic and neotectonic stages were characterized by a high degree of geodynamic activity, and the platform one by a decrease in contrast of tectonic movements. The main river net was formed in the Early Cretaceous and in the Neogene. It experienced a serious reconstruction accompanied by the formation of the Amur River valley being similar to the modem one.     

RXTE observations of the transient sources IGR J17091-3624 and IGR J18539+0727

We present the results of our analysis of the RXTE observations for two transient sources, IGR J17091-3624 and IGR J18539+0727, in April 2003. The derived energy spectra of the sources and the power-density spectra of their light curves make it possible to classify them as low/hard-state X-ray binaries. The parameters of the power spectrum for IGR J18539+0727 lead us to tentatively conclude that the compact object in this binary is a black hole.     

Chemical Enrichment of the Intra-Cluster Medium

We investigate the metal enrichment of the intra-cluster medium by using a method that combines N-Body simulations and a semi-analytic model (SAM) of galaxy formation. The cluster of galaxies is simulated in a flat, low density universe, with a numerical resolution that allows the detection of substructures in the dark matter background of the cluster. The phenomenological approach used to model the physical processes involved in the galaxy formation and metal production is applied to the substructures found in the dark matter halos detected at different redshifts. Details of the chemical implementation in the SAM and first results related to the mean properties of the baryonic matter components are presented. This revised version was published online in August 2006 with corrections to the Cover Date.