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Centro de Astrofísica da Universidade do Porto

Extended wind in jetless classical T Tauri star TW Hya

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

Abstract
We have conducted a spectro-astrometric (SA) analysis of high spectral resolution
data of the near infrared HeI 10830°A and Pa lines in the nearby classical T Tauri star TW Hya. We find clear position offsets associated to the blueshifted absorption part of the HeI 10830°A P Cygni profile. The derived spatial feature extend up to 50 mas (2.8AU at TW Hya distance) in two opposite directions. By using simple exploratory models we show that this feature can not be produced by the same stellar wind which 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.

The Astrophysical Journal
Volume 670, Page 1234
December 2007

Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

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