Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Eta Car through the eyes of interferometers   The core of the nebula surrounding Eta Carinae has recently been observed
with VLT/NACO, VLTI/VINCI, VLTI/MIDI and VLTI/AMBER in order to spatially and
spectrally constrain the warm dusty environment and the central object.
Narrow-band images at 3.74 and 4.05 micron reveal the structured
butterfly-shaped dusty environment close to the central star with an
unprecedented spatial resolution of about 60 mas. VINCI has resolved the
present-day stellar wind of Eta Carinae on a scale of several stellar radii
owing to the spatial resolution of the order of 5 mas (11 AU). The VINCI
observations show that the object is elongated with a de-projected axis ratio
of approximately 1.5. Moreover the major axis is aligned with that of the large
bipolar nebula that was ejected in the 19th century. Fringes have also been
obtained in the Mid-IR with MIDI using baselines of 75m. A peak of correlated
flux of 100 Jy is detected 0.3" south-east from the photocenter of the nebula
at 8.7 micron is detected. This correlated flux is partly attributed to the
central object but it is worth noting that at these wavelengths, virtually all
the 0.5" x 0.5" central area can generate detectable fringes witnessing the
large clumping of the dusty ejecta. These observations provide an upper limit
for the SED of the central source from 3.8 to 13.5 micron and constrain some
parameters of the stellar wind which can be compared to Hillier's model.
Lastly, we present the great potential of the AMBER instrument to study the
numerous near-IR emissive lines from the star and its close vicinity. In
particular, we discuss its ability to detect and follow the faint companion.

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The categories of this paper are: acc-phys
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The categories of this paper are: math
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-th
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The categories of this paper are: nlin
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: solv-int
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The categories of this paper are: q-fin
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The categories of this paper are: quant-ph
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The categories of this paper are: q-bio
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The categories of this paper are: cs
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The categories of this paper are: econ
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-ex
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The categories of this paper are: atom-ph