Extended Wind in Jetless Classical T Tauri Star TW Hya

Abstract

We have conducted a spectro-astrometric (SA) analysis of high spectral resolution data of the near-infrared He I λ10830 and Paγ lines in the nearby classical T Tauri star TW Hya. We find clear position offsets associated with the blueshifted absorption part of the He I λ10830 P Cygni profile. The derived spatial features extend up to 50 mas (2.8 AU at TW Hya distance) in two opposite directions. By using simple exploratory models we show that this feature cannot be produced by the same stellar wind that produces the P Cygni profile. Instead, we are able to reproduce the observed blueshifted SA profile with emission from a disk wind. The production of SA artifacts through instrumental effects was examined. Artifact models have difficulties in fitting both the PSF and the angular scale of the observed position spectra offsets, suggesting that the signal may be real.