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Extended wind in jetless classical T Tauri star TW Hya - Uncovering the inner structure of TW Hya with spectroscopy

R. Azevedo, D. F. M. Folha, J. F. Gameiro, N. Calvet

A spectro-astrometric (SA) analysis of high spectral resolution data of the near infrared HeI 10830Å and Pagamma lines in the nearby classical T Tauri star TW Hya is conducted, in search for extended emission. Clear position offsets associated to the blueshifted absorption part of the HeI 10830Å P Cygni profile are found using spectroastrometry. The derived spatial feature extend up to 50 mas (2.8AU at TW Hya distance) in two opposite directions. Recall that no jet has been associated to this star. By using simple exploratory models is shown that this feature can not be produced by the same stellar wind which produces the P Cygni profile. Instead, the observed blueshifted SA profile is reproduced with emission from a disk wind. The production of SA artifacts through instrumental effects was also 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.

XVIII Encontro Nacional de Astronomia e Astrofísica
Évora, Portugal
2008 September

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Faculdade de Ciências da Universidade de Lisboa Universidade do Porto Faculdade de Ciências e Tecnologia da Universidade de Coimbra
Fundação para a Ciência e a Tecnologia COMPETE 2020 PORTUGAL 2020 União Europeia