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Using multi-epoch Very Long Baseline Array observations, we have measured thetrigonometric parallax of the weak-line T Tauri star HP Tau/G2 in Taurus. Thebest fit yields a distance of 161.2 $\pm$ 0.9 pc, suggesting that the easternportion of Taurus (where HP Tau/G2 is located) corresponds to the far side ofthe complex. Previous VLBA observations have shown that T Tau, to the South ofthe complex, is at an intermediate distance of about 147 pc, whereas the regionaround L1495 corresponds to the near side at roughly 130 pc. Our observationsof only four sources are still too coarse to enable a reliable determination ofthe three-dimensional structure of the entire Taurus star-forming complex. Theydo demonstrate, however, that VLBA observations of multiple sources in a givenstar-forming region have the potential not only to provide a very accurateestimate of its mean distance, but also to reveal its internal structure. Theproper motion measurements obtained simultaneously with the parallax allowed usto study the kinematics of the young stars in Taurus. Combining the fourobservations available so far, we estimate the peculiar velocity of Taurus tobe about 10.6 km s-1 almost completely in a direction parallel to the Galacticplane. Using our improved distance measurement, we have refined thedetermination of the position on the HR diagram of HP Tau/G2, and of two othermembers of the HP Tau group (HP Tau itself and HP Tau/G3). Most pre-mainsequence evolutionary models predict significantly discrepant ages (by 5 Myr)for those three stars -expected to be coeval. Only in the models of Palla &Stahler (1999) do they fall on a single isochrone (at 3 Myr).

VLBA determination of the distance to nearby star-forming regions III. HP Tau/G2 and the three-dimensional structure of Taurus