may have been • mantle plume, but, alternatively, it may have been triggered by an asteroidal impact An impact fall-out layer with shocked debris has been reported at the Tr/J boundary in Italy [13]. The s ynchronicity of extrusion and extinction appear established as an event horizon independent of radiometric or fossil stratigraphy. Of course, enthusiasm for impacts does not score points in t...

Introduction: Asteroidal fragments in lunar breccias and soils are critical to an understanding of the nature of the major impactors of the Moon. Observing FeNi metal is typically the simplest way for identifying asteroidal fragments. Schreibersite [(Fe,Ni) 3 P] in FeNi metal is a clear indicator of asteroidal contamination , although this was validated only after the realization that schreiber...

A proper interval bigraph is a bigraph where to each vertex we can assign a closed interval such that the intervals can be chosen to be inclusion free and vertices in the opposite partite sets are adjacent when the corresponding intervals intersect. In this paper, we introduce the notion of astral triple of edges and along the lines of characterization of interval graphs via the absence of aste...

An induced matching in a graph G is a set of edges, no two of which meet a common node or are joined by an edge of G; that is, an induced matching is a matching which forms an induced subgraph. Induced matchings in graph G correspond precisely to independent sets of nodes in the square of the line-graph of G, which we denote by [L(G)]. Often, if G has a nice representation as an intersection gr...

Material collected from an asteroid’s surface can be used to increase gravitational attraction between the asteroid and a Gravity Tractor (GT); the spacecraft therefore operates more effectively and is referred to as an Enhanced Gravity Tractor (EGT). The use of tethers and solar sails to further improve effectiveness and simplify operations is investigated. By employing a tether, the asteroida...

We describe a significant practical consequence of taking anthropic biases into account in deriving predictions for rare stochastic catastrophic events. The risks associated with catastrophes such as asteroidal/cometary impacts, supervolcanic episodes, and explosions of supernovae/gamma-ray bursts are based on their observed frequencies. As a result, the frequencies of catastrophes that destroy...

extensive set of trajectories in both resonances. Moreover, we have included the 4/3 resonance in our study. The frequency map analysis was applied to the fairly realistic models of the 2/1, 3/2, and 4/3 jovian resonances and the Figure 1 shows the basic characteristics of the first-order results were compared with the asteroidal distribution at these mean–motion resonances in the averaged, pla...

Hilary Downes, David W Mittlefehldt, Pierre Hudon, Christopher S. Romanek and Ian Franchi Lunar and Planetary Institute, Houston, Texas, USA ([email protected]); School of Earth Sciences, Birkbeck, University of London, London, UK; NASA/Johnson Space Centre, Houston, Texas, USA; Dept. of Earth and Planetary Sciences, McGill University, Montreal, Quebec, Canada; 5 Savannah River Ecology Labora...

Recent studies show that chaotic motion should be considered as the rule rather than the exception in the asteroid belt, if the perturbations of many planets are taken into account. Assuming that asteroids are constantly diffusing away from the main belt, we may model their transport, i.e. the evolution of a distribution of initial conditions in the action space of the respective dynamical syst...