Issue |
A&A
Volume 434, Number 3, May II 2005
|
|
---|---|---|
Page(s) | 1005 - 1019 | |
Section | Interstellar and circumstellar matter | |
DOI | https://doi.org/10.1051/0004-6361:20042217 | |
Published online | 18 April 2005 |
Edge-on T Tauri stars
1
Landessternwarte, Königstuhl, 69117 Heidelberg, Germany e-mail: O.Stahl@lsw.uni-heidelberg.de
2
Institut d'Astrophysique, 98bis Bd. Arago, 75014 Paris, France
Received:
30
March
2004
Accepted:
8
January
2005
Using the Uves echelle spectrograph at the ESO VLT
we obtained two-dimensional high-resolution () spectra of
the edge-on disk objects HH30*, HK Tau B, and HV Tau C. For
comparison purposes we also observed with the same equipment both
the classical T Tauri star HL Tau and the active late-type star LDN
1551-9. The spectra of all three observed edge-on disks consist of
a T Tauri emission and absorption line spectrum with superimposed
jet emission lines. Analysis of the spectra confirmed that the disks
are completely opaque at visible wavelengths and that light from the
central objects reaches us only via scattering layers above and
below the disk planes. The central objects of our targets were found
to be normal T Tauri stars showing moderate but different amounts of
veiling of their photospheric spectra, indicating different
accretion rates or evolutionary stages. We suggest that all
classical T Tauri stars (CTTSs) show this observed morphology when
viewed edge-on. Part of the jet emission from edge-on systems is
directly visible to us in the forbidden lines as well as in
Hα and He i, a finding which contradicts the present
paradigm of a pure magnetospheric accretion origin for the formation
of hydrogen and helium emission lines in moderately active CTTSs.
From a comparison with those Taurus-Auriga CTTSs for which the
inclination is reliably known, we conclude that the view angle of
CTTS systems is one of the key parameters governing apparent
Hα emission strength in the T Tauri class. We discuss the
various possible formation regions for the Na i D lines and
show that profiles similar to observed ones can be formed at the
base of the disk wind.
Key words: stars: formation / stars: pre-main sequence / ISM: jets and outflows / planetary systems: proto-planetary disks / line: formation
© ESO, 2005
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