---------------------------------------------------------------------------- ------------ UNIVERSITIES SPACE RESEARCH ASSOCIATION Employee Name: Christian A. Hummel USRA Institute, Division, or Program: Division of Space Astronomy Government Sponsor: David Mozurkewich (NRL), Kenneth J. Johnston (USNO) Date: May 24th, 1996 EMPLOYEE RESEARCH SUMMARY General Description of your Research Activities: Data from the Navy Prototype Optical Interferometer (NPOI) did not arrive until the first quarter of 1996. Until then, I worked on the following: (1) A paper on the radio-loud quasar 0153+744. I completed maps and modelfits to data taken at 13cm, 6cm, 3.6cm, and 1.3cm, in collaboration with T. Krichbaum (MPIfR), W. Steffen (U of Manchester), and A. Fey (USNO). Source characteristics and parameters were determined, and I computed a precessing beam model for the radio jet structure. The paper will be submitted to Astronomy and Astrophysics sometime in June 1996. (2) A paper on Zeta Aurigae, in collaboration with P. Bennett et al. from JILA in Boulder, CO. The orbit for this spectroscopic binary was determined from data taken previously with the Mark III interferometer on Mt Wilson, CA. The paper was submitted to and accepted by the Astrophysical Journal in the first quarter of 1996. (3) Proposal, observations (in absentia), and data reduction of four spectroscopic binaries at the McMath Solar Telescope on Kitt Peak, in collaboration with D. Peterson of SUNY at Stonybrook. The data reduction of spectra from 14 nights is not yet completed. The aim is to complement data from the Mark III on bright binaries with spectroscopic orbits in order to determine the stellar masses. The interferometric data reduction of one of the binaries (Eta Pegasi) was finalized. (4) Compilation of a catalog of spectroscopic binaries for observations with the NPOI, consisting of about 300 system with estimated semi-major axes larger than 1 milliarcsecond. The catalog is based on the catalog by Batten et al., but more systems were added since the latter has not been updated since 1989. NPOI observations: With the arrival of data from the NPOI, I spent more time on data reduction and software issues. Two software packages, CHAMELEON and CONSTRICTOR (see previous annual report), were worked on extensively and used to examine and process the new data. Code added was for group delay fringe tracking and the reading and reformatting of metrology data. CHAMELEON was used to compute astrometric solutions for the baseline vectors, which were successfully used at NPOI for faster fringe aquisition. Closure phases were first observed May 19th. I worked extensively on the reduction of a data set taken on May 1st, which allowed calibration of data taken on the spectroscopic binary Zeta UMa with data from a nearby calibrator (Gamma UMa). I used my AMOEBA software (see my monthly reports) to show that a slightly modified orbit obtained with the Mark III for this binary provided a good fit to the visibility amplitudes, as well as to the closure phases. A calibrated set of the amplitudes and phases were imported into AIPS (with help from T. Pauls), and I was able to map the source using standard phase- selfcalibration methods for radio-interferometric data. This is only the second map made from optical interferometry data (the first one is due to the COAST group at Cambridge, UK). Description of Accomplishments for Reporting Period: (Be as detailed as possible). 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) Quirrenbach, A., Mozurkewich, D., Buscher, D.F., Hummel, C.A., Armstrong, J.T., 1996, A&A (in press) "Angular diameter and limb darkening of Arcturus" Quirrenbach, A., Bjorkman, K.S., Bjorkman, J.E., Hummel, C.A., Buscher, D.F., Armstrong, J.T., Mozurkewich, D., Elias II, N.M., Babler, B.L., 1996, A&A (in press) "Constraints on the geometry of circumstellar envelopes: optical interferometric and spectropolarimetric observations of seven Be stars" Bennett, P.D., Harper, G.H., Brown, A., Hummel, C.A., 1996, ApJ (in press) "The masses and radii of the eclipsing binary zeta Aurigae" Papers Submitted but not yet accepted for Publication: (include full citation and complete list of authors) Hummel, C.A., Krichbaum, T.P., Witzel, A., W\"ullner, K.H., Steffen, W., Alef, W., Fey, A., 1996, A&A (to be submitted) "The radio jet of quasar 0153+744" Papers Presented at Scientific Meetings: (Include invited Papers, contributed papers) "Observations of close binaries by optical long baseline interferometry", poster at Nato Advanced Study Institute on Evolutionary Processes in Binary Stars, Cambridge, UK, July 10 - 21, 1995 "Long Baseline Interferometry on Close Binaries", talk at 3rd Pacific Rim Conference on Recent Developments in Binary Star Research, Chiang Mai, Thailand, October 26 - November 1, 1995 "A precessing radio jet in quasar 0153+744", poster at 187th Meeting of the AAS, San Antonio, TX, January 14 - 18 "Double star astronomy with optical interferometers", poster at 187th Meeting of the AAS, San Antonio, TX, January 14 - 18, with J.T. Armstrong (NRL) "Interferometry of stars and quasars", talk at USRA Science Council Meeting, GSFC, March 1, 1996 "A precessing radio jet in quasar 0153+744", poster at Washington Area Astronomers Meeting, Johns Hopkins University, March 21, 1996 "Measurements of the visual orbits of spectroscopic binaries with long baseline optical interferometry", talk at the meeting of the Division of Dynamical Astronomy of the AAS, USNO, April 17, 1996 Participation in Scientific Meetings, Colloquia, Seminars, and Special Lectures: (include a listing of scientific meetings attended) Nato Advanced Study Institute on Evolutionary Processes in Binary Stars, Cambridge, UK, July 10 - 21, 1995 3rd Pacific Rim Conference on Recent Developments in Binary Star Research, Chiang Mai, Thailand, October 26 - November 1, 1995 187th Meeting of the AAS in San Antonio, TX, January 14 - 18 USRA Space Science Council Meeting, GSFC, March 1, 1996 Washington Area Astronomers Meeting, Baltimore, March 21, 1996 Membership in Professional Societies and Organizations: Member of Commission 26 (Double stars) of the IAU. Member of the American Astronomical Society 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.) Signature________________________ Date___________________