42.0            0.4      Nov 16 - Dec 16   110   this work
    s.dev             0.019    0.033    4.47      5.8        5.9            2.1                                            
              12.86   0.9915   0.1093   24.7     140.4       67.2          42.6                     Nov 16 - Dec 7    38     LIND99
              12.7             0.088    26.9     145.8       60.0          43.3                     Nov 16 - Nov 29   16      JEN06

![December Monocerotids, November Orionids and the comet C/1917 F1 Mellish in the phase space of perihelion distance and inclination.[]{data-label="F2"}](fig3.eps){width="8.0cm"}

As seen in Table 2 and Figures 1-3, the orbital distribution of the December Monocerotids and November Orionids have common features. There is good agreement in the geocentric velocity and minimal difference in the angular elements and eccentricity. The perihelion distance of the November Orionids is generally lower. It is worth pointing out that the perihelion distance of the MON and NOO showers is one of the lowest observed. Only a few meteor showers, among them the prominent Geminids, have such close perihelion distances. The dispersion of the MON and NOO orbital elements is relatively low, which gives the chance for good definition and differentiation of these showers.

The cumulative absolute magnitude distribution in Figure 4 shows that the population index of both showers is almost identical. However, NOO contains smaller particles, according to Figure 4. This 