  The asteroid (142) Polana is classified as a B-type asteroid located in the
inner Main Belt. This asteroid is the parent of the New Polana family, which
has been proposed to be the likely source of primitive near-Earth asteroids
such as the B-type asteroid (101955) Bennu. To investigate the compositional
correlation between Polana and Bennu at the 3-micron band and their aqueous
alteration histories, we analyzed the spectra of Polana in the ~2.0-4.0-micron
spectral range using the NASA Infrared Telescope Facility in Hawaii. Our
findings indicate that Polana does not exhibit discernable 3-micron hydrated
mineral absorption (within 2 sigma), which is in contrast to asteroid Bennu.
Bennu displayed a significant 3-micron absorption feature similar to CM- and
CI-type carbonaceous chondrites. This suggests two possibilities: either Bennu
did not originate from the New Polana family parented by asteroid Polana or the
interior of Bennu's parent body was not homogenous, with diverse levels of
aqueous alteration. Several explanations support the latter possibility,
including heating due to shock waves and pressure, which could have caused the
current dehydrated state of Bennu's parent body.
