There is now indication that solar systems with planetary distributions hospitable to life might be rather rare, even if planets as such are common.
The geographical coverage and the continuity of the data provide exclusive information on global distribution, seasonal variation, and planetary wave patterns.
In 1979 American astronomer Paul Weissman (the author of this article) published computer simulations of the Oort cloud energy distribution using planetary perturbations by Jupiter and Saturn and physical models of loss mechanisms such as random disruption and formation of a nonvolatile crust, based on actual observations of comets.
In this section we first study the spatial distribution of planetary O2+ ions (Section 3.1).
Planetary scientists suspect that this distribution of surface brightness is affected by the deposition of micrometre-sized ice particles from Saturn's E ring, in which Tethys is well-embedded.
Here we focus on how the structure of the magnetic field helps us to understand the spatial distribution of the planetary oxygen ions.
We followed the commonly accepted techniques of statistical analysis of impact craters on planetary bodies, crater size-frequency distribution (CSFD) (Crater Analysis Techniques Working Group 1979), to estimate the absolute model ages of the formation of the target areas.
Based on a modified version of the model of an induced martian magnetosphere developed by Luhmann (1990), the dynamics and spatial distribution of different planetary ion species is examined.
The measurements have provided global maps of the spatial distribution of the non-thermally escaping planetary O+ and O2+ ions and their energization when the solar wind accelerates planetary ions above the escape velocity (see, e.g. Barabash et al., 2007).
The progenitor must have mass not much in excess of a solar mass because of the distribution of the planetaries in the Galaxy.
