English: A plot of proper elements of 43,695 asteroids in the S- and X-type components of the Nysa-Polana complex of asteroid families, showing semi-major axis ${\displaystyle a}$ on the x-axis and absolute magnitude ${\displaystyle H_v}$ on the y-axis. Diameters of each circle are proportional to the diameter of the asteroid, which is closely correlated with ${\displaystyle H_v}$. White circles show the large asteroids 135 Hertha and 44 Nysa; Nysa is likely not part of the complex.

After an asteroid family is generated, asteroids of various sizes will spread out in semi-major axis over time due to the Yarkovsky effect. The rate at which they do so is inversely proportional to the asteroid's diameter, and the outer boundaries of this spread, shown as V-shaped curves, can be used to define asteroid families.

The blue asteroids (and curve) are from the 'Hertha1' asteroid family, and the yellow asteroids are in the 'Hertha2' family (as defined in terms of ${\displaystyle a}$, ${\displaystyle e}$, ${\displaystyle i}$, and Yarkovsky C ([1]) by Dykhuis and Greenberg (2015): [2]), which likely originated from separate impacts on Hertha. The Hertha1 family definition does not exactly match the orange curve due to a skew in its semi-major axis and eccentricity distribution. Gray asteroids do not belong to either family. Asteroids with albedos known to be less than 0.12 are not shown, as they largely belong to the overlapping C-type Eulalia and New Polana families.

Important orbital resonances are marked on the top of the plot; from right to left, these are the 3:1 Jupiter resonance (yellow), the 1:2 Mars resonance (red), and the three-body resonance ${\displaystyle {\alpha }_A=4{\alpha }_J-2{\alpha }_S}$ involving the mean motions of the asteroid, Jupiter, and Saturn.

Proper elements and absolute magnitudes are from a dataset by Nesvorný, 2026 [3]; diameters and albedos are provided by JPL SBDB for a subset of large asteroids [4].