Overview

This Project is focused on the study of the physical properties of different populations of minor bodies of the Solar System and their interactions: trans-Neptunian objects, Centaurs, comets and near-Earth asteroids, associated asteroids of the outer belt (e.g. Trojans), etc. The information obtained from their study is crucial to understand the origin and evolution of our planetary system.

Trans-Neptunian objects (TNOs), Centaurs and comets are three different but closely related populations of remnant planetesimals of the first stages of the Solar System, formed in the region of the protoplanetary disk where the giant planets are located, and up to about 50 AUs from the Sun. TNOs formed in a flat region beyond Neptune, known as the trans-neptunian belt or Edgeworth-Kuiper belt. Since the discovery of the first object in 1992, they have turned into some of the objects of most interest among the Solar System community, as they are a invaluable source of information about the composition and the conditions dominating that region of the pre-solar nebula. Due to gravitational perturbations and collisions, some TNOs are scattered to orbits located in the region of the giant planets, turning into Centaurs. Finally, and due to planetary perturbations (mainly with Jupiter), some Centaurs reach short-period orbits, with aphelia close to the orbit of Jupiter, and transform into Jupiter family comets (JFCs). On the other hand, long-period comets (LPCs) and Halley-type comets come from a spherical region in the outskirts of the Solar System, known as the Oort Cloud. The objects located in this cloud suffer from gravitational perturbations due to the gravitational field of the Galaxy, the passage of the Sun through molecular clouds, or the close passage of stars. This perturbations made some objects to be sent again to the internal region of the Solar System, approaching in some cases the Sun, in very eccentric orbits (LPCs). All this objects, TNOs, Centaurs and comets, have a common origin in the external region of the protoplanetary disk, and their study reveals important information about the state of the matter in that region, and about the processes that have taken place since the origin of the Solar System. Recent dynamical models suggest also that Trojans, Hildas and Cybeles could be TNOs that were scattered in the early stages of the Solar System.   

Other interesting objects are the near-Earth objects (NEOs), which constitute a population of minor bodies (asteroids and comets) whose orbits approach or intersect the orbit of the Earth. This objects come primarily from the main asteroid belt (MB), and in a minor percentage, from the population of Jupiter family comets. The study of NEOs presents a significant relevance from the astrophysical point of view, to the extent that they allow us to understand the transfer mechanisms of this population, and how it is constituted. Besides, they are, together with comets, the precursors of the majority of meteors and meteorites. Furthermore, due to their proximity to the Earth, several space missions have focused and will focus in a near future (e.g. NEAR or Deep Space 1) into  the detailed study of NEOs and comets.  However, those mission can only access a limited number of objects. In order to have a global understanding of the NEO population it is essential to study a significant number of members of the population from Earth. It is also remarkable that NEOs not only present a pure astrophysical interest, but they are also interesting from our security point of view, as they can collide with the Earth and are potentially hazardous for our civilization (in fact, there have been some impacts through the Earth's history). The relatively recent creation of programs to search and follow-up potentially hazardous NEOs, as well as the acknowledgement of the importance of their study by the European Council in their resolution of January 1996 to favour the development of international programs for the search and physical characterization of NEOs, are unequivocal signs of the relevance that the international community is giving to these objects.

To finish, besides the deactivated comets that can be found among the NEO population, there is a population of objects whose characteristics make difficult to clearly stablish their asteroidal or cometary nature, as they are asteroid-comet transitional objects. Among these objects are the asteroids in cometary orbits (ACOs) and the activated asteroids.