Employee Name: Christian A. Hummel

USRA Institute, Division, or Program: Division of Astronomy & Space Physics

Government Sponsor: David Mozurkewich (NRL)

Date: May 21, 1997


EMPLOYEE RESEARCH SUMMARY


General Description of your Research Activities:  (Be as detailed as possible)

Work in the past year was very much dominated by the reduction of data from 
the Navy Prototype Optical Interferometer (NPOI), which began observations 
in earnest during the second quarter of 1996. I have been in charge of most 
of the data reduction, and maintenance and development of the averaging, 
editing, and calibration software. A package written by me in the previous 
year (CHAMELEON) has now been extensively put to a test with the new data 
and has performed well. It was maintained and improved by me throughout the 
year. Another package (AMOEBA, formerly PICTOR), was built into a model 
computation and fitting program, using a hierarchical model format for 
multiple stellar systems. I plan to use the multiple star option for 
observations of triple stars, notably Algol and Eta Virginis.

I have taken over responsibility for scheduling observations, with input
from other project scientists on interesting stars. This also involves 
writing scheduling software, and implementing a database of relevant 
information on the observed and candidate stars.

Description of Accomplishments for Reporting Period: (Be as detailed as
possible).

(1)
Re-analysis of all 7 Mizar A maps of 1996, after a new bias correction
formula, derived by D. Mozurkewich, was implemented in CONSTRICTOR (i.e.
the raw data fringe fitting and averaging program, also maintained by me).
These maps are part of a paper submitted to the Astronomical Journal.

(2)
Related to the data reduction and calibration, a compilation of a list of
measured and estimated stellar diameters. Also, a full implementation of
limb-darkening coefficients and formulae in AMOEBA, obtained from tables
in electronic form published in ApJ.

(3)
Reduction and calibration of more than 40 nights of observations with NPOI.
Among these are 9 nights for the limb-darkened giant star Alpha Arietis,
where I showed that a uniform disk model does not fit the data well, but 
a limb-darkened disk does. (A paper on these results is in preparation.)
On the binary Omicron Leonis, 20 nights were reduced and a preliminary 
orbit was fitted to the data.

Describe any Significant Recognition of your work:



Honors or Awards Received: None



Papers Published or Accepted for Publication: (include complete
bibliographic citations; include complete list of authors)

Hummel, C.A., Krichbaum, T.P., Witzel, A., Wuellner, K.H., Steffen, W.,
	Alef, W., Fey, A., 1997, A&A (accepted)
	"The radio jet of quasar 0153+744"

Papers Submitted but not yet accepted for Publication: (include full
citation and complete list of authors)

Benson, J.A., Hutter, D.J., Elias II, N.M., Bowers, P.F., Johnston, K.J.,
	Hajian, A.R., Mozurkewich, D., Armstrong, J.T., Pauls, T.A.,
	Rickard, L.J, Hummel, C.A., White, N.M., Black, D., Denison, C.S.,
	1997, AJ (submitted)
	"Multichannel optical aperture synthesis imaging of Zeta 1 Ursae
	 Majoris with the Navy Prototype Optical Interferometer"

Hutter, D.J., Elias II, N.M., Peterson, E.R., Weaver, W.B., Weaver, G.,
	Mozurkewich, D., Vrba, F.J., Buscher, D.F., Hummel, C.A., 1997
	AJ (submitted)
	"Seeing tests at four sites in support of the NPOI project"

Papers Presented at Scientific Meetings: (Include invited Papers,
contributed papers)

"Images of Mizar A from long baseline optical interferometry", talk at the
	International Workshop Visual Double Stars, Formation and Evolutionary
	Tracks, held in Santiago de Compostela, Spain, July 29 - August 1, 1996

"Imaging and modeling of spectroscopic binaries by long baseline optical 
	interferometry", poster at the IAU Symposium No. 189, Fundamental 
	Stellar Properties: the Interaction of Observation and Theory, held 
	in Sydney, Australia, January 9 - 18, 1997

"A precessing jet in quasar 0153+744?", poster at the IAU Colloquium No. 164,
	Radio Emission from Galactic and Extragalactic Compact Sources,
	held in Socorro, New Mexico, April 21 - 26, 1997

Participation in Scientific Meetings, Colloquia, Seminars, and Special
Lectures:  (include a listing of scientific meetings attended)

International Workshop Visual Double Stars, Formation and Evolutionary
	Tracks, Santiago de Compostela, Spain, July 29 - August 1, 1996

IAU Symposium No. 189, Fundamental Stellar Properties: the Interaction of 
	Observation and Theory, Sydney, Australia, January 9 - 18, 1997

IAU Colloquium No. 164, Radio Emission from Galactic and Extragalactic Compact 
	Sources, Socorro, New Mexico, April 21 - 26, 1997

Membership in Professional Societies and Organizations:

American Astronomical Society
Deutsche Physikalische Gesellschaft
International Astronomical Union (member-elect)
Commission 26 (double stars) of the IAU




Collaborative Activities:  (include collaborative research projects
undertaken with university and non-university research groups)



Community Service:  (e.g. Offices in professional societies, lectures to
community or educational groups, consultation, etc.)



Additional Information:  (include any information you feel useful in
evaluating your performance such as books written or contributions to edited
books, grants/contract proposals submitted or funded, technical reports, etc.)










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