Constraining Disk Parameters of Be Stars Using Narrowband
H
Interferometry with the Navy Prototype Optical Interferometer
Christopher Tycner,1,2,3
G.C. Gilbreath,4
R.T. Zavala,2
J.T. Armstrong,4
J.A. Benson,2
Arsen R. Hajian,5
D.J. Hutter,2
C.E. Jones,6
T.A. Pauls,4 and
N.M. White7
1
Michelson Postdoctoral Fellow;
tycner@nofs.navy.mil
2
US Naval Observatory, Flagstaff Station, 10391 West Naval Observatory
Road, Flagstaff, AZ 86001-8521
3
NVI, Inc., 7257 Hanover Parkway, Suite D, Greenbelt, MD 20770
4
Remote Sensing Division, Code 7210, Naval Research Laboratory, 4555
Overlook Avenue SW, Washington, DC 20375
5
US Naval Observatory, 3450 Massachusetts Avenue NW, Washington,
DC 20392-5420
6
Department of Physics and Astronomy, University of Western Ontario,
London, ON N6A 3K7, Canada
7
Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001
Interferometric observations of two well-known Be stars,
 Cas and
 Per,
were collected and analyzed to determine the spatial characteristics
of their circumstellar regions. The observations were obtained using
the Navy Prototype Optical Interferometer equipped with custom-made
narrowband filters. The filters isolate the
H emission line from the
nearby continuum radiation, which results in an increased contrast
between the interferometric signature due to the
H-emitting
circumstellar region and the central star. Because the narrowband
filters do not significantly attenuate the continuum radiation at
wavelengths 50 nm or more away from the line, the interferometric
signal in the H channel is calibrated with
respect to the continuum
channels. The observations used in this study represent the highest
spatial resolution measurements of the
H-emitting regions of Be stars
obtained to date. These observations allow us to demonstrate for the
first time that the intensity distribution in the circumstellar region
of a Be star cannot be represented by uniform disk or ringlike
structures, whereas a Gaussian intensity distribution appears to be
fully consistent with our observations.
2006 AJ, 131, 2710
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tycner@nofs.navy.mil
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