For the objects that have properties that involve complex units, such as asteroid Bennu which has density and thermal inertia etc. to be returned, SBDB reports an error because the exponential in the units uses '^' rather than '**'.

from astroquery.jplsbdb import SBDB
sbdb = SBDB.query('bennu', phys=True)

Also it looks like astropy.units.Unit doesn't recognize decimal points when it's in the exponential. The decimal point has to be put inside a pair of parentheses. While this is an astropy issue, it affects how SBDB would parse units.

import astropy.units as u
print(u.Unit('m**(0.5)'))
print(u.Unit('m**0.5'))

astroquery==0.4.7.dev7713