that the NOO shower is older than the MON shower and both streams may originate from the same parent comet.

Resulting from the nodal distances of the comet and the relatively fast evolution of the ascending nodes of the showers (centuries), there is a possibility that we observe the outer edge of a widely evolved complex stream. The streams (MON and NOO) might be observed as two streams as a result of a geometric selection effect. Meteoroids with inclinations between the MON and NOO might have nodes on non-Earth crossing orbits.

Ejection of meteoroid particles from the parent comet
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The relatively large heliocentric distance of the ascending node of the parent comet and the much lower and stable semimajor axes of the meteors indicate that these particles were injected into these orbits immediately after ejection from the comet, while the comet might not have been on the same orbit at that time. The derivation of the ejection velocity depends on the model used. If we assume a spherical cometary nucleus with an albedo of $0.04$, active surface $0.15\%$ (@ma02, bulk density $750\,kg/m^3$, a radius of the nucleus 3.1km (@jen06), ejection at the perihelion $q\sim0.19$AU; and if the meteoroids are 