The so-called Nysa-Polana complex of asteroids is a diverse and widespread group studied by Cellino et al .
( 2001 , 2002 ) as a dynamically linked asteroid family .
It carries the name of two asteroids because it appears to be two overlapping families of different asteroid taxonomies : ( 44 ) Nysa is an E-type asteroid with the lowest number in the midst of a predominantly S-type cluster and ( 142 ) Polana is a B-type asteroid near the low-albedo B- and C-type cluster .
The latter has been shown to be a very important source of primitive Near Earth Asteroids .

Using the data from the Wide-field Infrared Survey Explorer ( WISE ) mission we have re-analyzed the region around the Nysa-Polana complex in the inner Main Belt , focusing on the low-albedo population .
( 142 ) Polana does not appear to be a member of the family of low-albedo asteroids in the Nysa-Polana complex .
Rather , the largest is asteroid ( 495 ) Eulalia .
This asteroid has never before been linked to this complex for an important dynamical reason : it currently has a proper eccentricity slightly below the range of most of the family members .
However , its orbit is very close to the 3:1 mean motion resonance with Jupiter and is in a weak secular resonance .
We show that its osculating eccentricity varies widely ( e = 0.06 - 0.19 ) on short timescales ( \sim 1 Myr ) and the averaged value diffuses ( between e = 0.11 - 0.15 ) over long timescales ( \sim 100 Myr ) .
The diffusive orbit , low-albedo , taxonomic similarity and semimajor axis strongly suggests that despite its current proper eccentricity , ( 495 ) Eulalia could have recently been at an orbit very central to the family .
Hierarchical Clustering Method tests confirm that at an eccentricity of e = 0.15 , ( 495 ) Eulalia could be the parent of the family .
The “ Eulalia family ” was formed between 900–1500 Myr ago , and likely resulted from the breakup of a 100–160 km parent body .

There is also compelling evidence for an older and more widespread primitive family in the same region of the asteroid belt parented by asteroid ( 142 ) Polana .
This family , the “ new Polana family ” , is more extended in orbital elements , and is older than 2000 Myr .