Issue |
A&A
Volume 377, Number 3, October III 2001
|
|
---|---|---|
Page(s) | 981 - 993 | |
Section | Stellar structure and evolution | |
DOI | https://doi.org/10.1051/0004-6361:20011124 | |
Published online | 15 October 2001 |
Direct multi-wavelength limb-darkening measurements of three late-type giants with the Navy Prototype Optical Interferometer
1
Universities Space Research Association (USRA), 300 D Street SW, Suite 801, Washington, DC 20024, USA Mailing address: U.S. Naval Observatory, AD5, 3450 Massachusetts Avenue NW, Washington, DC 20392, USA
2
U.S. Naval Observatory, 3450 Massachusetts Avenue NW, Washington, DC 20392, USA e-mail: cah@usno.navy.mil, kjj@astro.usno.navy.mil, hajian@usno.navy.mil
3
Naval Research Laboratory, Code 7210, Washington, DC 20375, USA e-mail: mozurk@rsd.nrl.navy.mil
4
Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001, USA e-mail: nmw@lowell.edu
Corresponding author: M. Wittkowski, mwittkow@eso.org
Received:
22
January
2001
Accepted:
9
August
2001
We present direct measurements of the limb-darkened intensity profiles
of the late-type giant stars HR 5299, HR 7635, and HR 8621 obtained
with the Navy Prototype Optical Interferometer (NPOI) at the Lowell
Observatory. A triangle
of baselines with lengths of 18.9 m, 22.2 m, and 37.5 m was used.
We utilized squared visibility amplitudes beyond the first minimum,
as well as triple amplitudes and phases in up to 10 spectral channels covering
a wavelength range of nm to
nm.
We find that our data can best be described by featureless symmetric
limb-darkened disk models while uniform disk and fully darkened disk
models can be
rejected. We derive high-precision angular limb-darkened
diameters for the three stars of 7.44 mas
0.11 mas,
mas, and
mas, respectively.
Using the HIPPARCOS parallaxes, we determine linear limb-darkened
radii of
,
,
and
, respectively.
We compare our data to a grid of Kurucz stellar model atmospheres, with
them derive the effective temperatures and surface gravities without
additional information, and find agreement with independent estimates
derived from empirical calibrations and bolometric fluxes. This
confirms the consistency of model predictions and direct observations
of the limb-darkening effect.
Key words: techniques: interferometric / techniques: high angular resolution / stars: fundamental parameters / stars: atmospheres / stars: late-type
© ESO, 2001
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