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

Abstract

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, ∣Vr∣ < 40 km s−1) and a high velocity component (HVC, ∣Vr∣ > 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 (Ṁ jet ) measured from the detected HVC [OI]6300Å line luminosity span from ∼10−13 to ∼10−7 M⊙ yr−1 and the corresponding Ṁ jet / Ṁ 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 Ṁ jet / Ṁ 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.