The outburst of the κ Cygnids in 2007: clues about the catastrophic break up of a comet to produce an Earth-crossing meteoroid stream

9 pages, 3 figures.-- Published online Nov 25, 2008.Using high-resolution, low-scan-rate, all-sky CCD cameras and high-level CCD video cameras, the Spanish Meteor and fireball Network (SPMN) recorded the 2007 κ Cygnid fireball outburst from several observing stations. Here, accurate trajectory, radiant and orbital data obtained for the κ Cygnid meteor are presented. The typical astrometric uncertainty is 1–2 arcmin, while velocity determination errors are of the order of 0.3–0.6 km s−1, though this depends on the distance of each event to the station and its particular viewing geometry. The observed orbital differences among 1993 and 2007 outbursts support the hypothesis that the formation of this meteoroid stream is a consequence of the fragmentation of a comet nucleus. Such disruptive process proceed as a cascade, where the break up of the progenitor body leads to produce small remnants, some fully disintegrate into different clumps of particles and other remaining as dormant objects such as 2008ED69, 2001MG1 and 2004LA12 which are now observed as near-Earth asteroids. In addition to the orbital data, we present a unique spectrum of a bright κ Cygnid fireball revealing that the main rocky components have chondritic abundances, and estimations of the tensile strength of those fireballs that exhibited a catastrophic disruption behaviour. All this evidence of the structure and composition of the κ Cygnid meteoroids is consistent with being composed by fine-grained materials typically released from comets.These results were partially achieved by using wide-field automatic digital cameras described in the Spanish patent application number 200501127, filed 2005 May, and later continued in the PCT document number PCT/ES06/070057. The authors would like to thank Instituto Nacional de Técnica Aeroespacial (INTA) and Consejo Superior de Investigaciones Científicas (CSIC) for the development of the all-sky CCD camera prototype in 2002. We also thank Professor J. Llorca (UPC) for his support. Finally, JMTR thanks Consejo Superior de Investigaciones Científicas (CSIC) for a JAE-Doc contract.Peer reviewe