  Prior to 2019, the June epsilon Ophiuchids (JEO) were known as a minor
unconfirmed meteor shower with activity that was considered typically moderate
for bright fireballs. An unexpected bout of enhanced activity was observed in
June 2019, which even raised the possibility that it was linked to the impact
of the small asteroid 2019 MO near Puerto Rico. Early reports also point out
the similarity of the shower to the orbit of the comet 300P/Catalina. We aim to
analyze the orbits, emission spectra, and material strengths of JEO meteoroids
to provide a characterization of this stream, identify its parent object, and
evaluate its link to the impacting asteroid 2019 MO. Our analysis is based on a
sample of 22 JEO meteor orbits and four emission spectra observed by the AMOS
network at the Canary Islands and in Chile. The link to potential parent
objects was evaluated using a combination of orbital-similarity D-criteria and
backwards integration of the orbit of comet 300P and the JEO stream. We confirm
the reports of an unexpected swarm of meteoroids originating in the JEO stream.
JEO meteoroids have low material strengths characteristic for fragile cometary
bodies, and they exhibit signs of a porous structure. The emission spectra
reveal slightly increased iron content compared to all other measured cometary
streams, but they are generally consistent with a primitive chondritic
composition. Further dynamical analysis suggests that the JEO stream is likely
to originate from comet 300P/Catalina and that it was formed within the last
1000 years. Over longer timescales, the meteoroids in the stream move to
chaotic orbits due to the turbulent orbital evolution of the comet. Our results
also suggest that the impact of the small asteroid 2019 MO on June 22 was not
connected to the JEO activity.
