September epsilon Perseid cluster as a result of orbital fragmentation

¹ Astronomical Institute, CAS, Fričova 298, 25165 Ondřejov, Czech Republic
e-mail: pavel.koten@asu.cas.cz
² Institut de Mécanique Céleste et de Calcul des Éphémérides, 77 avenue Denfert-Rochereau, 75014 Paris, France
³ Institute of Atmospheric Physics, CAS, 14131 Prague, (station Nýdek), Czech Republic

Received: 14 December 2016
Accepted: 13 February 2017

Abstract

Context. A bright fireball was observed above the Czech Republic on September 9, 2016, at 23:06:59 UT. Moreover, the video cameras at two different stations recorded eight fainter meteors flying on parallel atmospheric trajectories within less than 2 s. All the meteors belong to the September epsilon Perseid meteor shower. The measured proximity of all meteors during a very low activity meteor shower suggests that a cluster of meteors was observed.

Aims. The goal of the paper is first to determine whether this event was a random occurrence or a real meteor cluster and second, if it was a cluster, to determine the epoch and at what distance from the Earth the separation of the particles occurred.

Methods. The atmospheric trajectories of the observed meteors, masses, and relative distances of individual particles were determined using a double-station observation. According to the distances and masses of the particles, the most probable distance and time of fragmentation is determined.

Results. The observed group of meteors is interpreted as the result of the orbital fragmentation of a bigger meteoroid. The fragmentation happened no earlier than 2 or 3 days before the encounter with the Earth at a distance smaller than ~0.08 AU from the Earth.