Refereed publications: ---------------------- Hummel C.A., Schalinski C.J., Krichbaum T.P., Witzel A., Johnston K.J., 1988, A&A 204,68 "The quasar 0153+744" Witzel A., Schalinski C.J., Johnston K.J., Biermann P., Krichbaum T.P., Hummel C.A., Eckart A., 1988, A&A 206,245 "The occurence of bulk relativistic motion in compact radio sources" Eckart A., Hummel C.A., Witzel A., 1989, MNRAS 239,381 "Radio spectra of extragalactic sources and the relativistic beaming model" Quirrenbach A., Witzel A., Qian S.J., Krichbaum T., Hummel C.A., Alberdi A., 1989, A&A 226,L1 "Rapid radio polarization variability in the quasar 0917+624" Quirrenbach A., Witzel A., Krichbaum T., Hummel C.A., Alberdi A., Schalinski C., 1989, Nature 337,442 "Rapid variability of extragalactic radio sources" Krichbaum T.P., Hummel C.A., Quirrenbach A., Schalinski C.J., Witzel A., Johnston K.J., Muxlow T.W.B., Qian S.J., 1990, A&A 230,271 "The complex jet associated with the quasar 0836+71" Krichbaum T.P., Booth R.S., Kus A.J., Roennaeng B.O., Witzel A., Graham D.A., Pauliny-Toth I.I.K., Quirrenbach A., Hummel C.A., Alberdi A., Zensus J.A., Johnston K.J., Spencer J.H., Rogers A.E.E., Lawrence C.R., Readhead A.C.S., Hirabayashi H., Inoue M., Morimoto M., Dhawan V., Bartel N., Shapiro I.I., Burke B.F., Marcaide J.M., 1990, A&A 237,3 "43 GHz-VLBI observations of 3C273 after a flux density outburst in 1988" Qian S.J., Quirrenbach A., Witzel A., Krichbaum T.P., Hummel C.A., Zensus J.A., 1991, A&A 241,15 "A model for the rapid radio variability in the quasar 0917+624" Qian S.J., Witzel A., Krichbaum T., Quirrenbach A., Hummel C.A., Zensus J.A., 1992, Chin. Astron. Astrophys. (Acta Astron. Sin. 1991 32/4, 369-379) 16/2, 137 "Motion of knots in the superluminal source 3C 345" Hummel C.A., Schalinski C.J., Krichbaum T.P., Rioja M.J., Quirrenbach A., Witzel A., Muxlow T.W.B., Jonston K.J., Matveyenko L.I., Shevchenko A., 1992, A&A 257, 489 "The jets of quasar 1928+738: superluminal motion and large-scale structure" Quirrenbach A., Witzel A., Krichbaum T.P., Hummel C.A., Wegner R., Schalinski C.J., Ott M., Alberdi A., Rioja M., 1992, A&A 258,279 "Statistics of intraday variability in extragalactic radio sources" Krichbaum T.P., Witzel A., Graham D.A., Alef W., Pauliny-Toth I.I.K., Hummel C.A., Quirrenbach A., Inoue M., Hirabayashi H., Morimoto M., Rogers A.E.E., Zensus J.A., Lawrence C.R., Readhead A.C.S., Booth R.S., Roennaeng B.O., Kus A.J., Johnston K.J., Spencer J.H., Burke B.F., Dhawan V., Bartel N., Shapiro I.I., Alberdi A., Marcaide J.M., 1992, A&A 260, 33 "The evolution of the sub-parsec structure of 3C 84 at 43 GHz" Hummel C.A., Muxlow T.W.B., Krichbaum T.P., Quirrenbach A., Schalinski C.J., Witzel A., Johnston K.J., 1992, A&A 266, 93 "MERLIN and VLBI observations of the quasar 0836+710: Morphology of a parsec-kiloparsec scale jet" Armstrong J.T., Hummel C.A., Quirrenbach A., Buscher D.F., Mozurkewich D., Vivekanand M., Simon R.S., Denison C.S., Johnston K.J., Pan X.-P., Shao M., Colavita M.M., 1992, AJ 104, 2217 "The orbit of Phi Cygni measured with long-baseline optical interferometry: component masses and absolute magnitudes" Quirrenbach, A., Mozurkewich, D., Armstrong, J.T., Buscher, D.F., Hummel, C.A., 1993, ApJ 406, 215 "Angular diameter measurements of cool giant stars in strong TiO bands and in the continuum" Roos, N., Kaastra, J. S., Hummel, C.A., 1993, ApJ 409, 130 "A Massive Black Hole in 1928+738?" Quirrenbach A., Elias II N.M., Mozurkewich D., Armstrong J.T., Buscher D.F., Hummel C.A., 1993, AJ 106, 1118 "Observations of Nova Cygni 1992 with a Long-Baseline Interferometer" Quirrenbach A., Hummel C.A., Buscher D.F., Armstrong J.T., Mozurkewich D., Elias II N.M., 1993, ApJ 416, L25 "The asymmetric envelope of Gamma Cassiopeiae observed with the Mark III optical interferometer" Hummel C.A., Armstrong J.T., Quirrenbach A., Buscher D.F., Mozurkewich D., Simon R.S., Johnston K.J., 1993, AJ 106, 2486 "The spectroscopic binary Eta Andromedae: Determination of the orbit by optical interferometry" Hummel C.A., Mozurkewich D., Elias II N.M., Quirrenbach A., Buscher D.F., Armstrong J.T., Johnston K.J., Simon R.S., Hutter D., 1994, AJ 108, 326 "Four years of astrometric measurements with the Mark III optical interferometer" Also published in: Selected Papers on Long Baseline Stellar Interferometry, ed. by P.R. Lawson (SPIE Milestone Series 139), p.297 Hummel C.A., Armstrong J.T., Quirrenbach A., Buscher D.F., Mozurkewich D., Elias II N.M., Wilson R.E., 1994, AJ 107, 1859 "Very high precision orbit of Capella by long baseline interferometry" Quirrenbach A., Buscher D.F., Mozurkewich D., Hummel C.A., Armstrong J.T., 1994, A&A 283, L13 "Maximum-entropy maps of the Be shell star Zeta Tauri from optical long baseline interferometry" Ott M., Witzel A., Quirrenbach A., Krichbaum T.P., Standke K.J., Schalinski C.J., Hummel C.A., 1994, A&A 284, 331 "An updated list of radio flux density calibrators" Quirrenbach A., Mozurkewich D., Hummel C.A., Buscher D.F., Armstrong J.T., 1994, A&A 285, 541 "Angular diameters of the carbon stars UU Aur, Y CVn, and TX Psc from optical long-baseline interferometry" Quirrenbach A., Mozurkewich D., Buscher D.F., Hummel C.A., Armstrong J.T., 1994, A&A 286, 1019 "Phase-referenced visibility averaging in optical long-baseline interferometry" Buscher D.F., Armstrong J.T., Hummel C.A., Quirrenbach A., Mozurkewich D., Johnston K.J., Denison C.S., Colavita M.M., Shao M., 1995, Applied Optics, 34, 1081 "Interferometric seeing measurements on Mt. Wilson - power spectra and outer scales" Hummel C.A., Armstrong J.T., Buscher D.F., Mozurkewich D., Quirrenbach A., Vivekanand M., 1995, AJ 110, 376 "Orbits of small angular scale binaries resolved with the Mark III interferometer" Quirrenbach A., Mozurkewich D., Buscher D.F., Hummel C.A., Armstrong J.T., 1996, A&A 312, 160 "Angular diameter and limb darkening of Arcturus" Bennett P.D., Harper G.M., Brown A., Hummel C.A., 1996, ApJ 471, 454 "The masses and radii of the eclipsing binary Zeta Aurigae" 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., 1997, ApJ 479, 477 "Constraints on the geometry of circumstellar envelopes: optical interferometric and spectropolarimetric observations of seven Be stars" Hummel C.A., Krichbaum T.P., Witzel A., Wuellner K.H., Steffen W., Alef W., Fey A., 1997, A&A 324, 857 "The radio jet of quasar 0153+744" Benson J.A., Hutter D.J., Elias II N.M., Bowers P.F., Johnston K.J., Hajian A.R., Armstrong J.T., Mozurkewich D., Pauls T.A., Rickard L.J, Hummel C.A., White N.M., Black D., Denison C.S., 1997, AJ 114, 1221 "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 114, 2822 "Seeing tests at four sites in support of the NPOI project" Hajian A.R., Armstrong J.T., Hummel C.A., Benson J.A., Mozurkewich D., Pauls T.A., Hutter D.J., Elias II N.M., Johnston K.J., Rickard L.J, White N.M., 1998, ApJ 496, 484 "Direct confirmation of stellar limb darkening with the Navy Prototype Optical Interferometer" Armstrong J.T., Mozurkewich D., Rickard L.J, Hutter D.J., Benson J.A., Bowers P.F., Elias II N.M., Hummel C.A., Johnston K.J., Buscher D.F., Clark III J.H., Ha L., Ling L.-C., White N.M., Simon R.S., 1998, ApJ 496, 550 "The Navy Prototype Optical Interferometer" Hummel C.A., Mozurkewich D., Armstrong J.T., Arsen R. Hajian, Elias N.M. II, Hutter D.J., 1998, AJ 116, 2536 "Navy Prototype Optical Interferometer observations of double stars Mizar A and Matar" Lobanov A.P., Krichbaum T.P., Witzel A., Kraus A., Zensus J.A., Britzen S., Otterbein K., Hummel C.A., Johnston K., 1998, A&A 340, 60 "VSOP imaging of S5 0836+710: a close-up on plasma instabilities in the jet" Hummel C.A., White N.M., Elias II N.M., Hajian A.R., Nordgren T.E., 2000, ApJL, 540, 91 "Zeta Orionis A is a Double Star" Nordgren T.E., Armstrong J.T., Germain M.E., Hindsley R.B., Hajian A.R., Sudol J.J., Hummel C.A., 2000, ApJ, 543, 972 "Astrophysical Quantities of Cepheid Variables Measured with the NPOI" Armstrong J.T., Nordgren T.E., Germain M.E., Hajian A.R., Hindsley R.B., Hummel C.A., Mozurkewich D., Thessin, R.N., 2001, AJ, 121, 476 "Diameters of Delta Cephei and Eta Aquilae Measured with the Navy Prototype Optical Interferometer" Hummel C.A., Carquillat J.-M., Ginestet N., Griffin R.F., Boden A.F., Hajian A.R., Mozurkewich D., Nordgren T.E., 2001, AJ, 121, 1623 "Orbital and stellar parameters of Omicron Leonis from spectroscopy and interferometry" Wittkowski, M., Hummel C.A., Johnston K.J., Mozurkewich D., Hajian A.R., White N.M., 2001, A&A, 377, 981 "Direct multi-wavelength limb-darkening measurements of three late-type giants with the Navy Prototype Optical Interferometer" Hummel C.A., Benson J.A., Hutter D.J., Johnston K.J., Mozurkewich D., Armstrong J.T., Hindsley R.B., Gilbreath G.C., Rickard L.J, White N.M., 2003, AJ, 125, 2630 "First observations with a co-phased six-station optical long-baseline array: application to the triple star Eta Virginis" Mozurkewich D., Armstrong J.T., Hindsley R.B., Quirrenbach A., Hummel C.A., Hutter D.J., Johnston K.J., Hajian A.R., Elias II N.M., Buscher D.F., Simon R.S., 2003, AJ, 126, 2502 "Angular diameters of stars from the Mark III optical interferometer" Johnston, K.J., Fey, A.L., Gaume, R.A., Hummel, C.A., Garrington, S., Muxlow, T., Thomasson, P., 2004, ApJ, 604, 65 "The Enigmatic Radio Source T Tauri S" Johnston, K. J., Fey, A. L., Gaume R. A., Claussen, M. J., Hummel, C. A., 2004, AJ, 128, 822 "Recent Observations of the Centimeter Radio Emission from the T Tauri System" Britzen S., Krichbaum T.P., Strom R., Witzel A., Muxlow T.W.B., Matveenko L.I., Campbell R.M., Alef A., Hummel C.A., Zensus A., 2004, A&A, (submitted) "Large-scale motion, oscillations and a possible halo/counter-jet in 1803+784" Zwahlen N., North P., Debernardi Y., Eyer L., Galland F., Groenewegen M.A.T., Hummel C.A., 2004, A&A (accepted) "A purely geometric distance to the binary star Atlas, a member of the Pleiades" Harper G.M., Brown A., Bennett P.D., Baade R., Walder R., Hummel C.A., 2004, ApJ, (submitted) "NRAO VLA observations of Zeta Aurigae: confirmation of the slow acceleration wind density structure" Non-refereed publications: -------------------------- Schalinski C.J., Witzel A., Krichbaum T.P., Hummel C.A., Biermann P.L., Johnston K.J., Simon R.S., 1988, in "The impact of VLBI on astrophysics and geophysics", ed. by M.J. Reid and J.M. Moran (Dordrecht: Kluwer), p.71 "Bulk relativistic motion in a complete sample of flat spectrum radio sources" Hummel C.A., Krichbaum T.P., 1990, in "Parsec-scale radio jets", ed. by J.A. Zensus and T.J. Pearson (Cambridge: Cambridge University Press), p.38 "The jet in quasar 0836+71" Hummel C.A., 1990, in "Compact steep-spectrum & GHz-peaked spectrum radio sources", ed. by C. Fanti, R. Fanti, C.P. O'Dea and R.T. Schilizzi (Bologna: Consiglio Nazionale delle Ricerche, Istituto di Radioastronomia), p.172 "The compact flat spectrum double 0153+744" Hummel C.A., 1991, in "Variability of active galaxies", ed. by W.J. Duschl, S.J. Wagner and M. Camenzind (Berlin: Springer), p.193 "VLBI knots and superluminal motion" Hummel, C.A., Armstrong, J.T., 1992, in "Complementary Approaches to Double and Multiple Star Research", ed. by H.A. McAlister and W.I. Hartkopf (San Francisco: PASP), p.552 "Binary Orbits from Interferometric Data" Hummel C.A., 1993, in "Sub-arcsecond Radio Astronomy", ed. by R.J. Davis and R.S. Booth (Cambridge: Cambridge University Press), p.403 "Astrometry with optical interferometers" Roos N., Kaastra J.S., Hummel C.A. 1994, in "The Nature of Compact Objects in Active Galactic Nuclei", ed. by A. Robinson and R.J. Terlevich (Cambridge: Cambridge University Press), p.377 "A Massive Binary Black Hole in 1928+738?" Hummel C.A., Armstrong J.T. 1994, in "Very High Angular Resolution Imaging", ed. by J.G. Robertson and W.J. Tango (Dordrecht: Kluwer), p.410 "Mark III Interferometer: milliarcsecond 'visual' orbits of Spectroscopic Binaries" Hummel C.A. 1995, in "Astronomical and Astrophysical Objectives of Sub-milliarcsecond Optical Astrometry", ed. by E. Hoeg and P.K. Seidelmann (Dordrecht: Kluwer), p.19 "Single and Double Star Astrometry with the Mark III Interferometer" Hummel C.A. 1997, in "The Third Pacific Rim Conference on Recent Development of Binary Star Research", ed. by K.-C. Leung (San Francisco: PASP), p.19 "The Mark III Interferometer Spectroscopic Binary Program" Hummel C.A. 1997, in "Visual Double Stars: Formation, Dynamics and Evolutionary Tracks", ed. by J.A. Docobo, A. Elipe, and H. McAlister (Dordrecht: Kluwer), p.55 "Images of Mizar A from long baseline optical interferometry" Hummel C.A., Benson J.A. 1997, in "Fundamental Stellar Properties: the Interaction of Observation and Theory", ed. by T. Bedding (Sydney: School of Physics), p.6 "Images of Mizar A and other results from NPOI" Johnston K.J., Hutter D.J., Benson J.A., Elias II N.M., Armstrong J.T., Mozurkewich D., Pauls T.A., Hummel C.A. 1997, in "Fundamental Stellar Properties: the Interaction of Observation and Theory", ed. by T. Bedding (School of Physics: Sydney), p.39 "Astrometry using interferometry at optical wavelengths" Otterbein K., Krichbaum T.P., Kraus A., Witzel A., Hummel C.A., Zensus J.A., in "Radio Emission from Galactic and Extragalactic Compact Sources", ed. by J.A. Zensus, G.B. Taylor, and J.M. Wrobel (San Francisco: PASP), p.73 "S5 0836+710 A Kelvin-Helmholtz Unstable Jet on Parsec Scales?" Hummel C.A., in "Radio Emission from Galactic and Extragalactic Compact Sources", ed. by J.A. Zensus, G.B. Taylor, and J.M. Wrobel (San Francisco: PASP), p.61 "The Radio Jet of Quasar 0153+744" Armstrong J.T., Mozurkewich D., Pauls T.A., Hajian A.R., Hummel C.A. 1998, in "The tenth Cambridge workshop on cool stars, stellar systems, and the Sun", ed. by R. Donahue and J. Bookbinder (San Francisco: ASP conference Series), CD-1931, ARMSTRJ1 "Limb-darkening observations and binary-star images from the Navy Prototype Optical Interferometer" Pauls T.A., Mozurkewich D., Armstrong J.T., Hummel C.A., Benson J.A., Hajian A.R. 1998, in "Astronomical Interferometry", ed. by R.D. Reasenberg (Bellingham: SPIE), p.467 "Observations of Stellar Limb Darkening with the Navy Prototype Optical Interferometer" Hutter D.J., Elias N.M. II, Hummel C.A. 1998, in "Astronomical Interferometry", ed. by R.D. Reasenberg (Bellingham: SPIE), p.452 "First astrometric results from NPOI" Hummel C.A. 1998, in "Astronomical Interferometry", ed. by R.D. Reasenberg (Bellingham: SPIE), p.483 "Images of Spectroscopic Binaries with the Navy Prototype Optical Interferometer" Hummel C.A. 1999, in "Precise Stellar Radial Velocities", ed. by J.B. Hearnshaw and C.D. Scarfe (San Francisco: PASP), p.416 "Imaging and Modeling of Double Stars with the Navy Prototype Optical Interferometer: a Continuation of the Mark III Double Star Program" Hummel C.A. 1999, in "Working on the Fringe", ed. by S.C. Unwin and R.V. Stachnik (San Francisco: PASP), p.44 "Imaging and Modeling of Binaries with NPOI" Hummel C.A. 2000, in "Interferometry in Optical Astronomy", ed. by P.J. Lena and A. Quirrenbach (Bellingham: SPIE), p.459 "The practice of Interferometry with NPOI" Hummel C.A. 2000, in Birth and Evolution of Binary Stars, poster proc. IAU Symp. 200, ed. by B. Reipurth \& h. Zinnecker (Potsdam: Astrophysikalisches Institut), p.154 "Images and orbits of multiple stars with NPOI" Quirrenbach A., Mozurkewich D., Armstrong T., Buscher D., Hummel C., 2001, in "Galaxies and their constituents at the highest angular resolution", ed. by R.T. Schilizzi, S.N. Vogel, F. Paresce, and M.S. Elvis (San Fransisco: PASP), p.304 "Cool giant stars are bigger at 712 nm than at 754 nm" Wittkowski M., Hummel C. A., 2003, in "Interferometry for Optical Astronomy II", ed. by W.A. Traub (Bellingham: SPIE), p.210 "Interferometric measurements of stellar intensity profiles" Benson J.A., Hummel C. A., Mozurkewich D., 2003, in "Interferometry for Optical Astronomy II", ed. by W.A. Traub (Bellingham: SPIE), p.358 "Simultaneous 6-station observations with the NPOI" Hummel C.A., Mozurkewich D., Benson J. A., Wittkowski M., 2003, in "Interferometry for Optical Astronomy II", ed. by W.A. Traub (Bellingham: SPIE), p.1107 "Coherent integration using phase bootstrapping" BAAS Abstracts: ---------- Armstrong J.T., Hummel C.A., Mozurkewich D., et al. 1991, BAAS 23, 1412 "Stellar masses from the Mark III optical Interferometer" Elias N.M., Quirrenbach A., Armstrong J.T., Buscher D., Hummel C.A., Mozurkewich D. 1992, BAAS 24, 1189 "Interferometric observations of Nova Cygni 1992" Hutter D.J., Elias N.M., Hindsley R.B., Hummel C.A., Armstrong J.T., Buscher D.F., Mozurkewich D., Johnston K.J., Westerhout G., White N.M. 1993, BAAS 183, 7307 "The USNO Astrometric Interferometer" Elias N.M., Hummel C.A., Mozurkewich D., Quirrenbach A., Buscher D.F., Armstrong J.T., Johnston K.J., Simon R.S., Hutter D.J. 1993, BAAS 183, 7309 "Four years of astrometric measurements with the Mark III Optical Interferometer" Hummel C.A., Armstrong J.T. 1993, BAAS 183, 8604 "Orbits of double stars from long baseline optical interferometry" Bennett P.D., Harper G.M., Brown A., Hummel C.A. 1994, BAAS 185, 8520 "A re-analysis of the zeta Aurigae binary system" Hummel C.A., Krichbaum T.P., Witzel A., Steffen W. 1995, BAAS 187, 1208 "A precessing beam in radio quasar 0153+74?" Armstrong J.T., Hummel C.A. 1995, BAAS 187, 4303 "Double star astronomy with optical interferometers" Benson J.A., Hutter D.J., Elias N.M., Bowers P., Mozurkewich D., Armstrong J.T., White N., Hummel C. 1996, BAAS 188, 5410 "The Navy Prototype Optical Interferometer" Pauls T.A., Mozurkewich D., Armstrong J.T., Hajian A.R., Hummel C.A. 1997, BAAS 191, 1231 "Limb-Darkening Observations with the Navy Prototype Optical Interferometer" Hutter D.J., Elias II N.M., Hummel C.A. 1997, BAAS 191, 1234 "First Astrometric Results from the NPOI" Armstrong J.T., Mozurkewich D., Pauls T.A., Rickard L.J, Benson J.A., Dyck H.M., Elias II N.M., Hajian A.R., Hummel C.A., Hutter D.J., Johnston K.J., White N.M. 1997, BAAS 191, 1234 "The Navy Prototype Optical Interferometer (NPOI) is Operational" Hummel C.A. 1997, BAAS 191, 1277 "Images of Spectroscopic Binaries with the Navy Prototype Optical Interferometer" Nordgren T.E., Dyck M., Sudol J., Germain M., Hummel C.A., Benson J.A. 1998, BAAS 192, 917 "Stellar Angular Diameters and Linear Radii from Optical Interferometry" Hummel C.A., Hutter D.J., Elias N.M. II. 1999, BAAS 194, 955 Double star and wide angle astrometry with NPOI" Codes: A&A : Astronomy and Astrophysics ApJ : Astrophysical Journal AJ : Astronomical Journal MNRAS: Monthly Notices of the Royal Astronomical Society