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Asteroids

The Asteroid Belt (Credit: NASA/JPL-Caltech)

Asteroids are thought to be remnant material from the processes of formation and initial development of planets and therefore sources of information on the conditions in the early solar system. Through subsequent bombardment such bodies have significantly influenced the evolution of the terrestrial planets and may have contributed to the conditions needed for the development of life on Earth. Ironically, impacts of asteroids and comets on the Earth may also present one of the greatest threats to the long-term survival of mankind.

Most asteroids orbit in the so-called main belt which lies between the orbits of Mars and Jupiter. Collisions between asteroids in the main belt give rise to fragments, the orbits of which can evolve under the effects of thermally emitted radiation (Yarkovsky effect) and the gravitational influence of planets, primarily Jupiter. Such objects can become Mars- or Earth-crossers, meaning that their orbits bring them within the orbits of these planets. The population of small bodies known as near-Earth objects (NEOs) consists mainly of such objects, together with some nuclei of evolved or extinct comets. NEOs come close enough to the Earth to allow them to be studied in detail with groundbased and orbiting telescopes. Knowledge of the sizes, surface properties and compositions of NEOs is essential for investigations of their origins, their relation to main-belt asteroids, comets and meteorites, the role they have played in the development of the Earth and the threat they pose to civilization as potential impactors on the Earth.

Work carried out by the Department addresses these questions and provides crucial information for the preparation and planning of fly-by and lander missions to asteroids. Activities of Department members include:

• Thermal infrared and optical observations of asteroids, using observatories such as the the Spitzer Space Telescope, Keck, NASA Infrared Telescope Facility, ESO, Calar Alto.
• Modelling the thermal emission of asteroids to derive sizes, albedos, and information on surface properties, such as thermal inertia, from telescope data.
• Concept studies, design, hardware development and operation of space missions to asteroids (e.g. DAWN, AsteroidFinder, ASTEX, NEOMAP).
• Research into the physical and dynamic properties of asteroids and their size distributions.
• Simulations of orbital evolution over large time scales.
• Simulations of the impacts of asteroids and comets on planets.
• Investigations of the role played by asteroids and comets in the development of planets and life on Earth.
• Maintenance of a an on-line data-base of physical and dynamical properties NEOs, with the corresponding bibliographical references (EARN).

The development of software for the modelling of asteroids and comets and the simulation of the performance of space instrumentation is an important part of the work of the Department.

For up-to-date details of the activities of Department personnel, see the latest report. You will find a link on the right menu bar.