Metric approaches to identify a common origin of objects in σ-Capricornids complex

The related association between the objects of the σ-Capricornids asteroid meteoroid complex has been examined. The complex consists of five NEAs (including Adonis), and of the σ-Capricornids meteoroid stream which produce four active meteor showers observable on the Earth. The relation between the NEAs and the stream was previously suggested as a result of studying the NEAs orbital evolution, determination the theoretical features of meteor showers associated with NEAs, and identification the predicted showers with the observable ones that are generated by the σ-Capricornids meteoroid stream. We have measured the distances between the NEAs orbits and followed them backward for the period of 40 kyrs using the known criteria of orbital similarity, such as the DSH and Dr criteria, and recently proposed metrics ϱ2,ϱ3, and ϱ4, as well as the results of calculation of orbital evolution. It turned out, that the NEAs orbits had the minimal mutual distance about 5.5 kyrs ago. This moment may coincide with a break-up of the parent comet of the σ-Capricornids complex. At present the NEAs of this family with high probability represent the large sized extinct fragments of this comet-progenitor.