X-Shooter Survey of Jets and Winds in T Tauri Stars

Summary

We report the results of a survey on the [OI]6300Å line emission in 131 T Tauri stars of the Lupus, Chamaeleon and σ Orionis star forming regions, observed with the X-shooter spectrograph at the Very Large Telescope (VLT). The line profile was deconvolved into a low velocity component (LVC, ∣V_r∣ <  40 km s⁻¹) and a high velocity component (HVC, ∣V_r∣ >  40 km s⁻¹), originating from slow winds and high velocity jets, respectively. The LVC is by far the most frequent component, with a detection rate of 77%, while only 30% of sources have a HVC. The [OI]6300Å luminosity of both the LVC and HVC, when detected, correlates with stellar and accretion parameters of the central sources with similar slopes for the two components. Mass ejection rates (${\dot {M}_{jet}}$) measured from the detected HVC [OI]6300Å line luminosity span from ∼10⁻¹³ to ∼10⁻⁷ M_⊙ yr⁻¹ and the corresponding ${\dot {M}_{jet}}$/${\dot {M}_{acc}}$ ratio ranges from ∼0.01 to ∼0.5, with an average value of 0.07. However, considering the upper limits on the HVC, we infer a ${\dot {M}_{jet}}$/${\dot {M}_{acc}}$ ratio < 0.03 in more than 40% of sources. We argue that most of these sources might lack the physical conditions needed for an efficient magneto-centrifugal acceleration in the star-disc interaction region.