The Astronomy faculty included Marek Demianski, Visiting Professor of Astronomy and Acting Director of the Hopkins Observatory; Karen B. Kwitter, Professor of Astronomy (Chair); and Karen A. Gloria, Instructor in Astronomy and Observatory Supervisor. Field Memorial Professor of Astronomy Jay M. Pasachoff was on leave at the Harvard-Smithsonian Center for Astrophysics.
Marek Demianski continued his research on relativistic astrophysics and cosmology. With P. Ivanov and D.I. Novikov from the Astro Space Center in Moscow, he studied an inflationary model of very early evolution of the universe with a continuous but non-smooth potential. Results of this research have been summarized in a paper "Resonance scales in the galaxy correlation function and the nature of dark matter," which was issued as a NORDITA preprint in March 1994 and was accepted for publication in the Physical Review. Results of an investigation of cosmological perturbations with a group of Italian collaborators (S. Capazziello, R. de Ritisi and C. Rubano) were presented at a conference on "The birth and evolution of the universe" (Rome, May 1994) and were submitted for publication in the Physical Review. The parameter which characterizes these perturbations can be specified by comparing predicted perturbations with observational constraints on the microwave background fluctuations.
With Fronefield Crawford '94, Demianski constructed three models of neutron stars based on available equations of state of very dense matter. They compared their predictions with the observed masses of neutron stars and glitches or "star quakes" observed in radio pulsars. The predictions of two of the three models were in reasonable agreement with observations. Results of this investigation will be submitted for publication.
With Alex Wong '94, Demianski constructed a simple model of a spiral galaxy. They incorporated recent results on the dark matter component of spiral galaxies. The presence of dark matter enhanced the instability of the disk. Only a few orbits were investigated, and on the basis of these results they suspect that there are many orbits which represent chaotic motion.
During this academic year, Demianski gave several lectures and invited talks. In December 1993 at the Copernicus Center in Warsaw and at the University of Warsaw, he gave a talk on the 1993 Nobel Prize in Physics. In January 1994 at the University of Warsaw, he gave an intense 4- week-long graduate course on "Black Hole Astrophysics." In April at the Royal Astronomical Society and European Astronomical Society meeting in Edinburgh, Demianski gave an invited review talk on "Microwave Background Radiation." During the spring semester (March 21 - April 2, and May 30 - June 11) at the University of Warsaw, Demianski gave an intense 4 week long graduate course on Cosmology. In September 1993, Demianski was elected a member of an International Scientific Committee organizing the Seventh Marcel Grossmann meeting on General Relativity which will be held at Stanford (July 25 - 29, 1994). Demianski will chair one of the parallel sessions and present an invited talk.
This spring, Observatory Supervisor, Karen Gloria, and student research assistant, Henry Roe '97, used the observatory's 24-inch telescope and CCD camera to monitor the brightness variations of several RR Lyrae stars, in collaboration with Astronomer Andrew Layden of Cerro Tololo International Observatory in Chile. Layden will be using Gloria and Roe's data as part of a study of the kinematics and distribution of RR Lyrae stars in the Galactic halo.
The Williams College observatory had the good fortune to be on the southern limit of the path of the annular solar eclipse of May 10, 1994. Karen Gloria used the observatory's 6-inch apochromatic refractor and CCD camera to obtain a series of images through the annularity phase of the eclipse. These images are invaluable to astronomers studying small scale variations in the orbit of the Moon. Information from these images has been sent to Roger Sinnott, of Sky & Telescope magazine, who is studying discrepancies between different calculations of the elements for the May 10 eclipse.
During the summer of 1993, Karen Gloria used the CCD camera, 6-inch telescope, and DEC workstation to create an image mosaic of NGC 6992, the Veil Nebula. This image mosaic was published in the premier issue (spring, 1994) of the magazine CCD Astronomy.
Karen Gloria used the department's DEC workstation to construct a World Wide Web home page for Williams College Astronomy. The home page features current research results of faculty, staff, and students as well as information on the observatory facilities (plus great images taken by Williams faculty, staff, and students!).
Kwitter has continued her studies of planetary nebula halos. Kwitter's discovery of a halo around the Owl Nebula has been followed by a paper submitted to Astronomy and Astrophysics, entitled "A Halo of Red Giant Wind Around the Owl Nebula," with Arturo Manchado (Instituto de Astrofísica of the Canary Islands), You-Hua Chu (University of Illinois at Urbana-Champaign), and Martín Guerrero (Instituto de Astrofísica of the Canary Islands). This confirms the Owl Nebula as a member of the rare class of known triple-shell planetary nebulae.
Kwitter's studies of old planetary nebulae continue with Richard Tweedy (Steward Observatory, University of Arizona). In September 1993, Bonnie Schulkin '96 participated in an observing run with Tweedy to take spectra of the outer portions of old planetary nebulae at the Multiple-Mirror Telescope on Mt. Hopkins, near Tucson. Henry Roe '97 accompanied Kwitter and Tweedy on an observing run to Kitt Peak National Observatory in April 1994. They observed with a large-format CCD detector at the Burrell Schmidt telescope. Tweedy and Kwitter have submitted two papers on their results, which include discovery of planetary nebulae around two hot white dwarf stars.
Kwitter is also continuing to work on carbon abundances in planetary nebulae. Carbon is tricky in that the only emission line appearing in the visible part of the spectrum is a transition in singly ionized carbon, C+, which is intrinsically very weak compared to the normally observed emission lines in these objects. Summer 1993 Keck Northeast Astronomy Consortium (KNAC) exchange student Oliver DeWolfe (Wesleyan '96) and Williams student Fronefield Crawford '94 used a sophisticated computer modeling program, CLOUDY, to derive carbon abundances in these planetary nebulae, based on emission line intensities. Along with Richard Henry (University of Oklahoma) and his graduate student James Buell, Kwitter is working under the auspices of a two-year NASA Astrophysics Data Program grant to use newly recalibrated archived data from the International Ultraviolet Explorer satellite to study the production of carbon in intermediate-mass stars. Summer 1994 students Corey Olsen '96 and Keck exchange student Chris Mazzurco (Wesleyan '96) continued the work of their predecessors.
Kwitter is continuing a collaboration with Don Lubowich (American Institute of Physics/Hofstra University) to search for lithium in planetary nebulae. Lithium enrichment has been documented in main-sequence stars, giant stars, and pre-planetary nebula stars; this investigation proposes to continue the search farther along the evolutionary path to planetary nebula envelopes. Using the coudé-feed telescope with an echelle spectrograph on the 36-inch telescope at Kitt Peak National Observatory, they have obtained high-dispersion spectra of several bright planetary nebulae. These nebulae were chosen because they exhibit neutral sodium emission and/or absorption; the presence of neutral sodium is a tracer for neutral lithium, since their ionization potentials are within a few tenths of an eV of each other. Lubowich, along with James Partan '94, obtained spectra of a few more bright planetary nebulae in May 1994; the data are in the process of analysis.
Kwitter's CCD image of the Owl Nebula from the Burrell Schmidt telescope and a spectrum she obtained of Comet Halley at the 2.1-m telescope at Kitt Peak in 1986 were selected for inclusion on an astronomy videodisk assembled by Optical Data Corporation.
During 1993-94, Jay M. Pasachoff was on sabbatical leave and on leave at the Harvard- Smithsonian Center for Astrophysics as Visiting Scientist, Smithsonian Astrophysical Observatory, and Visiting Lecturer in Astronomy, Harvard University. He was an Associate of Kirkland House, Harvard College. At the Center for Astrophysics, he was associated with the High-Energy Astrophysics Division, and, sponsored by a NASA Education grant, worked on developing educational software descriptions of x-ray astronomy and the Advanced X-Ray Facility project. He also began on a project, jointly with Fred Seward of the CfA, on Rosat (Roentgen Satellite) observations of the galactic clusters h and chi Persei.
Pasachoff continued his positions as U.S. National Representative for Commission 46 (The Teaching of Astronomy) of the International Astronomical Union (I.A.U.); Chair of the Working Group on Eclipses of Commission 12 on the Radiation and Structure of the Solar Atmosphere of the I.A.U.; and as a member of the Scientific Organizing Committee for Commission 46 at the Hague General Assembly of the I.A.U., August 1994. He was I.A.U. Representative to the International Council of Scientific Unions--Committee on Teaching of Science, 1991-94 and in this capacity he attended the CTS meeting in Paris in July 1993, and served on the advisory boards of the American Association of Variable Star Observers educational project (NSF Curriculum Grant); the Astronomical Society of the Pacific (NSF Curriculum Grant A-ASTRO); Odyssey, a children's magazine (Cobblestone Publishing); and the Physical Science Board, World Book. He also reviewed several books for AAAS Science Books and Films,
In his role as a member of the Working Group on Education of the American Astronomical Society, he organized and chaired a session on "Curriculum Projects in Astronomy Education" at the January 1994 Washington meeting.
Pasachoff presented talks at Konkoly Observatory of the Hungarian Academy of Sciences in Budapest, Wellesley College, Harvard-Smithsonian Center for Astrophysics, and the U.S. Coast Guard Academy. He also spoke at StarConn, the amateur astronomers meeting at Wesleyan and at a meeting of the Amateur Telescope Makers of Boston. He began a term as a Sigma Xi National Lecturer with a presentation at SUNY-Cortland.
Pasachoff received a grant for $75,000 from the Getty Foundation to write a book about "Art and Astronomy in Britain, 1710-1860" jointly with Prof. Roberta J. M. Olson of the Art Department at Wheaton College. He will be on leave during 1994-95 for this purpose. The research will include month-long trips to the United Kingdom, with work at London, Edinburgh, and Cambridge.
Much of Pasachoff's research was devoted to studies of the heating of the solar corona and to observations planned for the 3 November 1994 total solar eclipse in South America. It will be his 21st central solar eclipse. The research is aimed at discovering how the outer layers of the sun, the solar corona, get to a temperature of 2,000,000 kelvins in spite of their being above cooler layers. He received the renewal of his NSF grant for studies of coronal heating by surface Alfvén waves, and received a grant from the National Geographic Society for eclipse observations of coronal temperature through ultraviolet photometric studies. The latter uses the Keck CCD. Undergraduate students are participating in the work both in Williamstown and on the eclipse site. Bonnie Schulkin '96 has worked both the summers of 1993 and 1994 on the project in Williamstown. Kevin Reardon '92, now working at the Institute for Astronomy of the University of Hawaii, is also participating in the planning and in the expedition. Dr. Bryce Babcock, Staff Physicist at the Bronfman Science Center of Williams College, is Pasachoff's chief collaborator. Zadig Mouradian of the Observatoire de Paris is also collaborating on one of the experiments.
Pasachoff investigated eclipse sites in Chile and Bolivia one year prior to the eclipse, in October-November 1993, and chose a site in an Indian village of Putre, Chile, 144 km inland from Arica at an altitude of 3500 m. In his role as Chair of the Working Group on Eclipses of the International Astronomical Union, he has made this into an international site for professional astronomers from the US, India, France, Belgium, Japan, Korea, Chile, and prospectively, other countries.
In September 1993, Pasachoff delivered papers entitled "Coronal Morphology and Heating-Mechanism Observations at Total Eclipses Through 1992," and "Total Solar Eclipses, 1994-1999" at the International Astronomical Union Colloquium 144 on Solar Coronal Structures at Tatranská Lomnica, Slovakia.
Pasachoff continued his work on interstellar deuterium and its cosmological consequences, jointly with Donald A. Lubowich of the American Institute of Physics and Hofstra University. Undergraduate students inside and outside of the Keck Consortium continued work with Tom Balonek of Colgate and Pasachoff on studies of Kitt Peak National Observatory spectral observations, searching for deuterium-alpha in the wing of hydrogen-alpha in hot stars. They are also reducing data from a National Radio Astronomy Observatory run with the 12-m telescope on Kitt Peak in which they found deuterated HCN in the Sgr A source in the center of our galaxy. Students involved in this project include Keck summer students Christy A. Tremonti and Eric Spaulding (Colgate undergraduates with Pasachoff at Williams), Robert P. Galloway '96, and Ann Mancuso, a Hofstra undergraduate. A paper was delivered on the latter subject at the January 1994 American Astronomical Society meeting and a paper for the Astrophysical Journal is in preparation.
Under the guidance of Karen Gloria, the 24" telescope and associated electronics continued to be used successfully in the astronomy curriculum. Students used the CCD detector to obtain images, and then manipulated them using several image processing packages. Teaching assistants this year were Patrick Barnard '95, Fronefield Crawford '94, Jason DeLuce '95, Jason Lorentz '96, Corey Olsen '96, James Partan '94, Bonnie Schulkin '96, Alexia Rosoff '96, and Sarah Rispin '96. Sean Sandys '94 and Kyle Downey '96 were the System Managers for the astronomy workstations.
With assistance from Karen Gloria, several first- and second- year students used the observatory facilities to conduct research projects as part of Astronomy 106, a "hands-on" course in observational astronomy taught by Visiting Professor Marek Demianski. The research projects were: "Searching for Supernovae," Michelle Adams '97, and Colleen Melia '97; "Photographing Atmospheric Phenomena," Robbi Behr '97, Dung Ho '96, and Anuradha Idupuganti '97; "Monitoring Jupiter's Atmosphere," Jesse Brackenbury '97, and Emily Button '97; "Color CCD Imagery," Bryan Greenhouse '96, Ingrid Lau '97, Josh Lawton '97, Patty Pai '97, and Akiko Yamagata '97; "Monitoring Hubble's Variable Nebula," Jennifer Lockhart '97, and Christine Soares '97; "Polarimetry of Celestial Objects," Christina Reynolds '97; and "Monitoring Sunspots," Patty Scott '96.
Much of the work for these research projects made use of the CCD camera, 24-inch and 6- inch telescopes, filters and filter wheels provided with the assistance of grants from the Keck foundation and the Kresge Foundation. Many of the students used the department's DEC workstation to access information on their research topics from public ftp sites and World Wide Web sites at various astronomy research institutions around the country.
The Milham Planetarium was operated by Bob Galloway '96, Amy MacDougal '95, and Brienna Perelli '96. The fall show was entitled "Magellan: Report from Venus" the spring show was designed by the planetarium TA's, and concentrated on constellations.
Williams had a strong showing at the 4th annual Keck Northeast Astronomy Consortium student conference, held at Wellesley in October 1993. Kwitter attended, along with students Fronefield Crawford '94, Brett Schneider '94 Chris Welch '94, Jason DeLuce '95, Kyle Downey '96, Bob Galloway, '96, and Bonnie Schulkin '96.