Context : In a recent study , individual parallaxes were determined for many stars of the Taurus-Auriga T association that are members of the same moving group .
We use these new parallaxes to re-address the issue of the relationship between classical T Tauri stars ( CTTSs ) and weak-emission line T Tauri stars ( WTTSs ) .
With the available spectroscopic and photometric information for 72 individual stars or stellar systems among the Taurus-Auriga objects with known parallaxes , we derived reliable photospheric luminosities , mainly from the I _ { c } magnitude of these objects .
We then studied the mass and age distributions of the stellar sample , using pre-main sequence evolutionary models to determine the basic properties of the stellar sample .
Statistical tests and Monte Carlo simulations were then applied to studying the properties of the two T Tauri subclasses .
We find that the probability of CTTS and WTTS samples being drawn from the same parental age and mass distributions is low ; CTTSs are , on average , younger than WTTSs .
They are also less massive , but this is due to selection effects .
The observed mass and age distributions of both T Tauri subclasses can be understood in the framework of a simple disk evolution model , assuming that the CTTSs evolve into WTTSs when their disks are fully accreted by the stars .
According to this empirical model , the average disk lifetime in Taurus-Auriga is 4 \cdot 10 ^ { 6 } ( M _ { * } / M _ { \odot } ) ^ { 0.75 } yr .

Aims :

Methods :

Results : stars : formation , stars : pre-main sequence , stars : fundamental parameters , ( stars ) : circumstellar matter

Conclusions :