  The paper presents an analysis of homogeneous long-term photometric
observations of 28 well-known weak-line T Tauri stars (WTTS) and 60 WTTS
candidates detected by the ROSAT observatory in the direction of the
Taurus-Auriga star-forming region. 22 known WTTS and 39 WTTS candidates are
shown to exhibit periodic light variations that are attributable to the
phenomenon of spotted rotational modulation. The rotation periods of these
spotted stars lie within the range from 0.5 to 10 days. Significant differences
between the long-term photometric behaviors of known WTTS and WTTS candidates
have been found. We have calculated accurate luminosities, radii, masses, and
ages for 74 stars. About 33 percent of the sample of WTTS candidates have ages
younger than 10 Myr. The mean distance to 24 WTTS candidates with reliable
estimates of their radii is shown to be 143+/-26 pc.
