Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observations of T-Tauri Stars using HST-GHRS: II. Optical and Near UV
  lines   We have analyzed GHRS data of eight Classical T Tauri stars (CTTSs) and one
Weak T Tauri star (WTTS). The GHRS data consist of an spectral range 40 A wide
centered on 2800 A. For 4 of the CTTS we have nearly simultaneous optical
observations which contain Halpha, Hbeta, HeI, NaD, and the CaII infrared
triplet. The MgII resonance doublet is the strongest feature in the 2800 A
range. This line has a fairly wide and symmetric emission component (~200 to
\~300 km/s for the CTTSs), with a narrow central absorption and a wide
blueshifted absorption superimposed to it. The narrow central absorption width
and equivalent width are inconsistent with being due only to ISM clouds
described in the literature, which lead us to conclude that it is partially due
to non-LTE processes in the emission line region itself. The emission profile
closely follows Halpha. Its large width in CTTS cannot be due to the Stark
effect and we suggest that it is due to supersonic turbulence. All the stars
show blueshifted absorptions that are evidence of outflows (terminal velocities
\~300 km/s), with multiple flows observed in two stars. We show evidence that
the wind is not spherical, with wind signatures being stronger for lower
inclinations at a given accretion rate. We briefly compare other optical lines
with the hot transition region lines observed in CTTS.

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The categories of this paper are: hep-lat
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The categories of this paper are: math
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
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The categories of this paper are: adap-org
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The categories of this paper are: econ
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The categories of this paper are: comp-gas
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int
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The categories of this paper are: plasm-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: nlin
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The categories of this paper are: q-fin
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The categories of this paper are: math-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: alg-geom