Publications of the MPIfR
Optical & Infrared
Interferometry Group
O. Chesneau, R. van Boekel, T. Herbst,
P. Kervella, M. Min, L.B.F.M. Waters, Ch. Leinert,
R. Petrov, G. Weigelt
Eta Car through the eyes of interferometers
(invited)
"ESO Astrophysics Symposia"
Proceedings of the ESO Workshop: "The power of
optical/IR interferometry: recent scientific results and 2nd generation
VLTI instrumentation"
April 4-8, 2005 in Garching, Germany
Abstract
The core of the nebula surrounding Eta Carinae has been observed
recently with VLT/NACO, VLTI/VINCI, VLTI/MIDI and VLTI/AMBER to con-
strain spatially and spectrally the warm dusty environment and the
central object.
Narrow-band images at 3.74 µm and 4.05 µm 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 on
a scale of 5 mas
(~ 11 AU) provided by 25m projected baselines. 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 and a peak of correlated flux at 100 Jy
level situated
0.3” south-east from the photocenter of the nebula at 8.7 µm is
detected. This
correlated flux is partly attributed to the central object but it is
worth noting that
at these wavelength virtually all the 0.5”x0.5” central area can
generate detectable
fringes witnessing the large clumping of the dusty ejecta. These
observations pro-
vide an upper limit for the SED of the central source from 3.8 µm to
13.5 µm
and constraint some parameters of the stellar wind which can be
compared to the
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.
You can get this publication ...