  The Habitable Worlds Observatory Preliminary Input Catalog (HPIC) is a list
of ~13,000 nearby bright stars that will be potential targets for the Habitable
Worlds Observatory (HWO) in its search for Earth-sized planets around Sun-like
stars. We construct this target list using the TESS and Gaia DR3 catalogs, and
develop an automated pipeline to compile stellar measurements and derived
astrophysical properties for all stars. We benchmark the stellar properties in
the HPIC relative to those of the manually curated ExEP HWO Precursor Science
Stars list and find that, for the 164 best targets for exo-Earth direct
imaging, our stellar properties are consistent. We demonstrate the utility of
the HPIC by using it as an input for yield calculations to predict the science
output of various mission designs including those with larger telescope
diameters and those focused on other planet types besides Earth analogs, such
as Jupiter-mass planets. The breadth and completeness of the HPIC is essential
for accurate HWO mission trade studies, and it will be useful for other
exoplanet studies and general astrophysics studying the population of bright
nearby stars.
