Imposible el viaje del ponente por el temporal de nieve en EEUU
Michael Zolensky
Astromaterials Research and Exploration Science
NASA Johnson Space Center, Houston, TX
The sample return capsule of the Stardust spacecraft was successfully recovered on January 15, 2006, and its cargo of coma grains from the Jupiter-family Comet Wild-2 has now been the subject of intense investigation by approximately 200 scientists scattered across five continents for the past 4 years. The mineralogy and chemistry of over 200 harvested Wild-2 grains reveal to us a rudimentary understanding of the fine-grained mineralogy of the comet, and forces us to reconsider the origin and evolution of comets. The expectation of many workers was that the comet would be shown to consist of either (1) mainly amorphous materials, (2) materials exactly like interplanetary dust particles, or (3) mainly be preserved presolar materials. Many people assumed that the cometary organics would all have been completely fried during capture in the aerogel, and that phases such as carbonates and sulfides would all be melted or worse during capture. Almost everyone believed that whatever materials we recovered from the mission would have originated at the edge of the early solar nebula, if not still further away. We now know that all of these ideas were wrong. Crystalline materials predominate in Comet Wild-2 grains, and there are significant differences between them and interplanetary dust particles. Presolar grains are extremely rare. The grain capture process was in fact very hard on many grains, but it worked well enough to preserve some volatile organics species, numerous sulfides and even some carbonates. The biggest surprise was probably the high abundance of inner solar system solids among the comet grains, requiring the action of a large-scale outer grain transport mechanism in the early solar system.
12 de febrero de 2010. 12:00h
Auditorio Centro de Astrobiologia CSIC-INTA
Instituto Nacional de Técnica Aeroespacial
Ctra de Ajalvir, km 4
28850 Torrejón de Ardoz, Madrid
Para facilitar el acceso a recinto del Inta es recomendable contacto previo vía correo electrónico sanchezvr@inta.es
