  We report Keck/HIRES and HST/COS spectroscopic studies of extrasolar rocky
planetesimals accreted onto two hydrogen atmosphere white dwarfs, G29-38 and GD
133. In G29-38, 8 elements are detected, including C, O, Mg, Si, Ca, Ti, Cr and
Fe while in GD 133, O, Si, Ca and marginally Mg are seen. These two extrasolar
planetesimals show a pattern of refractory enhancement and volatile depletion.
For G29-38, the observed composition can be best interpreted as a blend of a
chondritic object with some refractory-rich material, a result from
post-nebular processing. Water is very depleted in the parent body accreted
onto G29-38, based on the derived oxygen abundance. The inferred total mass
accretion rate in GD 133 is the lowest of all known dusty white dwarfs,
possibly due to non-steady state accretion. We continue to find that a variety
of extrasolar planetesimals all resemble to zeroth order the elemental
composition of bulk Earth.
