  I have used high-precision photometry and astrometry from the third data
release of Gaia to perform a survey for members of the TW Hya association
(TWA). I have identified candidate members that appear to share similar
kinematics and ages with bona fide members compiled by Gagne et al. (2017) and
I have assessed their membership using radial velocities and spectroscopic
diagnostics of age from various sources. My new catalog of adopted members
contains 67 Gaia sources in 55 systems. The histogram of spectral types for TWA
peaks near M5 (~0.15 Msun), resembling the distributions measured for other
nearby young associations. The UVW velocities of its members indicate that the
association is expanding. The rate of expansion corresponds to an age of
9.6+0.9/-0.8 Myr. In a Gaia color-magnitude diagram, the members of TWA exhibit
well-defined sequences of single stars and unresolved binary stars. The
combined sequence of low-mass stars in TWA is indicative of an age of
11.4+1.3/-1.2 Myr when compared to the sequence for Upper Centaurus-Lupus/Lower
Centaurus-Crux, for which an age of 20 Myr is assumed. Based on these expansion
and isochronal ages, I have adopted an age of 10+/-2 Myr for TWA. Finally, I
have used mid-infrared photometry from the Wide-field Infrared Survey Explorer
to check for excess emission from circumstellar disks among the TWA members.
Fourteen members have detected disks, all of which have been reported in
previous studies. The fraction of members at <=M6 (>=0.1 Msun) that have full,
transitional, or evolved disks is 10/52=0.19+0.08/-0.06. That value is similar
to the fraction previously measured for the Upper Sco association, which is
roughly coeval with TWA.
