The Taurus-Auriga association and its associated molecular cloud are a benchmark population for studies of star and planet formation .
The census of Taurus-Auriga has been assembled over seven decades and has inherited the biases , incompleteness , and systematic uncertainties of the input studies .
The notably unusual shape of the inferred IMF and the existence of several isolated disk-bearing stars suggest that additional ( likely disk-free ) members might remain to be discovered .
We therefore have begun a global reassessment of the membership of Taurus-Auriga that exploits new data and better definitions of youth and kinematic membership .
As a first step , we reconsider the membership status of every disk-free star with spectral type later than F0 , 3 ^ { h } 50 ^ { m } < \alpha < 5 ^ { h } 40 ^ { m } , and 14 \degr < \delta < 34 \degr that we have found to be suggested as a candidate member in the literature .
We combine data from the literature with Keck/HIRES and UH88/SNIFS spectra to test the membership of these candidates using their HR diagram positions , proper motions , radial velocities , H \alpha emission , lithium absorption , and surface gravity diagnostics .
Out of 396 candidate members , there are 218 confirmed or likely Taurus members , 160 confirmed or likely interlopers , and only 18 that still lack sufficient evidence to draw firm conclusions .
A significant fraction of these stars ( 81 / 218 = 37 \% ) are not included in the most recent canonical member lists .
Intriguingly , there are few additional members to the immediate vicinity of the molecular clouds , preserving the IMFs that have been deemed anomalous in past work .
Many of the likely Taurus members are distributed broadly across the search area .
When combined with the set of all known disk hosts , our updated census reveals two regimes : a high-density population with a high disk fraction ( indicative of youth ) that broadly traces the molecular clouds , and a low-density population with low disk fraction ( hence likely older ) that most likely represents previous generations of star formation .
There is preliminary evidence of spatial and kinematic structure , including a possible link to the nearby 32 Ori association , though the lack of parallaxes prevents unambiguous interpretation of differences in sky position , RV , and proper motion .