Astronomy Department

Faculty of the Astronomy Department included Jay M. Pasachoff, Field Memorial Professor of Astronomy, Chair, and Director of the Hopkins Observatory; Karen B. Kwitter, Ebenezer Fitch Professor of Astronomy (on sabbatical leave); Marek Demianski, Visiting Professor of Astronomy; and Steven P. Souza, Instructor in Astronomy and Observatory Supervisor. Bryce A. Babcock, recently retired as Staff Physicist and Coordinator of Science Facilities, was appointed Associate of the Hopkins Observatory.

On the steps of the President’s House before the Weinberg lecture. (left to right) Naomi Pasachoff, Jay Pasachoff, Frederic Strauch, Adam Falk, Marek Demianski, Louise Weinberg, Steven Weinberg, Karen Kwitter, Steven Souza, Daniel Aalberts, Jefferson Strait

Pasachoff and Souza participated with MIT colleagues in observations of the occultation of a star by Pluto on July 3, 2010, from Santiago, Chile, working with Muzhou Lu’12 and Keck Northeast Astronomy Consortium (KNAC) Summer Fellow Craig Malamut (Wesleyan’12) [Souza operated the camera remotely from Williamstown]. Pasachoff had arranged other telescopes in Chile to participate in the observations. The Williams-MIT collaboration attempted observations of the Kuiper-belt object Ixion on July 18, 2010 from Williamstown and other sites in the Northeast, though no occultation was seen. Pasachoff and Babcock, in collaboration with their MIT colleagues, prepared for, arranged, and observed from two telescopes in Hawaii in February 10, 2011, to try to capture an occultation of a star by the Kuiper-belt object Varuna, also one of the trans-Neptunian objects. On May 22, 2011, Souza used the on-campus 0.6-m telescope with a POETS (Portable Occultation, Eclipse, and Transit System), one of three that Williams College has through a NASA equipment grant, to successfully observe an occultation of a star by Pluto, showing a diminution of the total intensity of the star + Pluto by about 20% for about 100 seconds. Also present for the observations were Pasachoff, Babcock, Matt Hosek’12 and Shubhanga Pandey’13. The results are being used to refine the model of Pluto’s and Charon’s orbits and will improve the predictions of the currently planned observations from two telescopes in Hawaii of the June 22/23, 2011, occultation of both Pluto and Charon and the June 26/27 occultation of Pluto with the possibility of an additional occultation by its moon Hydra. The work is supported by a research grant from NASA. Caroline Ng’11 during the summer of 2010 prepared a Website at http://www.stellaroccultations.info to gather links to the various work the Williams faculty and students have carried out to study the outer solar system through observing those objects occulting distant stars.

Pasachoff with former KNAC Summer Fellow Evan Tingle (Wesleyan ’08) published their analysis of the fine structure of the solar chromosphere, supported in part by a grant from NASA’s Marshall Space Flight Center. Ingolf Dammasch of the Royal Observatory Belgium, and Alphonse Sterling from NASA’s Marshall Space Flight Center, were collaborators. The observations were taken in conjunction with simultaneous observations of the same features in the ultraviolet from NASA’s Transition Region and Coronal Explorer (TRACE) spacecraft. Tingle used Pasachoff’s Solar Ultraviolet Measurement of Emitted Radiation (SUMER) observations of chromospheric motions spectroscopically, and tied them in with TRACE observations that showed an overlapping chromospheric loop, with the material held in place by solar magnetism. Pasachoff, Tingle, Sterling and Dammasch, had their paper appear in the journal Solar Physics.

Pasachoff observed the total solar eclipse of July 11, 2010, from Easter Island, working with Muzhou Lu’13 and KNAC Summer Fellow Craig Malamut (Wesleyan’12). They had previously observed the July 3 Pluto occultation from Santiago, Chile. In the analysis of the results, which include a comparison with observations made from Tatakoto in French Polynesia 83 minutes earlier, they worked with Hana Druckmüllerová and Miloslav Druckmüller of the Brno Technical University, Czech Republic, and Vojtech Rusin and Metod Saniga of the Astronomical Institute in Tatranská Lomnica, Slovakia. They compared with space observations from NASA’s Solar Dynamics Observatory, the European Space Agency’s PRoject for Onboard Autonomy (PROBA2), ESA’s and NASA’s Solar and Heliospheric Observatory, and NASA’s Solar Terrestrial Relations Observatory (STEREO), and included colleagues Leon Golub and Alec Engell of the Harvard-Smithsonian Center for Astrophysics, Daniel B. Seaton ’01 of the Royal Observatory of Belgium, Steele Hill of NASA’s Goddard Space Flight Center, and Rob Lucas of the University of Sydney, Australia, as co-authors of the paper for The Astrophysical Journal. They described two coronal mass ejections as they moved through space during the interval between observations at the two eclipse island sites, as well as changes in a polar plume. See also Pasachoff’s podcast about the total eclipse of July 11: http://365daysofastronomy.org/2010/07/10/july-10th-total-solar-eclipse-in-easter-island. Pasachoff had an Op-Ed piece in The New York Times on eclipse day, “Why I Never Miss a Total Eclipse.”

Pasachoff worked with John Seiradakis and Aris Voulgaris of the Aristotle University of Thessaloniki, Greece, on papers for Solar Physics about chromospheric and coronal spectra taken at the total eclipses. The spectra show the decline in overall coronal temperature with the sunspot cycle, and provide a new way of determining the length of totality and of the flash spectrum through such spectral observations.

A film crew accompanied the team on Easter Island from Naked Science on the National Geographic Channel that made the Easter Island Eclipse program. It aired the evening of eclipse day, July 11, 2010; clips are available on YouTube in 5 parts at:

http://www.youtube.com/view_play_list?p=9748EB4F9967520F

Pasachoff continued his work on transits of Mercury and Venus across the face of the sun, collaborating with Glenn Schneider of the Steward Observatory of the University of Arizona. In additional collaboration with Thomas Widemann of l’Observatoire de Paris, they published a detailed analysis of their observations of the 2004 transit of Venus from NASA’s TRACE spacecraft in The Astronomical Journal. Venus’s atmosphere appeared as refracted light during the second half of ingress and the first half of egress, each lasting about 25 minutes of visibility. Widemann and Paolo Tanga at the l’Observatoire de Côte d’Azur in Nice related the transit observations to Venus Express spacecraft observations of the Cytherean atmosphere’s circulation. See our Website at http://www.transitofvenus.info, which includes both historical information and information about current research at Williams College about transits of Venus and Mercury.

Pasachoff and Schneider, in collaboration with Babcock, Kevin Reardon ’82, Widemann, and Tanga planned observations for the June 5, 2012, transit of Venus, the last such transit to be seen until the year 2117. They obtained commitments of telescope time at Haleakala, Hawaii, at Sacramento Peak Observatory, New Mexico, and at Kitt Peak, Arizona, and with spacecraft including NASA’s new Solar Dynamics Observatory, the American Solar Optical Telescope, on the Japanese Hinode spacecraft, and NASA’s ACRIMsat (Active Cavity Radiometer Irradiance Measurement satellite) and SORCE/TIM (SOlar Radiation and Climate Experiment/Total Irradiance Measurement).

Pasachoff continued work on the interstellar medium, especially through considerations of the cosmic deuterium abundance. He works in collaboration with Donald Lubowich of Hofstra University.

Pasachoff continued his work with art-historian Roberta J. M. Olson of the New-York Historical Society. They delivered a paper at the seventh meeting on The Inspiration of Astronomical Phenomena, INSAP7, held in Bath, England. See http://www.insap.org. They discussed the comets discovered in the 18th century by Caroline Herschel who, with her brother William, started observing from Bath.

Pasachoff observed the partial solar eclipse of January 5, 2011, from Tel Aviv, Israel, and the partial solar eclipse of June 1, 2011, from Reykjavik, Iceland. They were his 52nd and 53rd solar eclipses. Descriptions and images appear at http://www.williams.edu/astronomy/eclipse. He received a research grant from the National Science Foundation for himself, Babcock, and students to study the sun at the two 2012 solar eclipses in Australia and the Western United States.

During the academic year 2010/ 2011 Marek Demianski continued his study of the process of condensation of matter that leads to formation of galaxies and clusters of galaxies leaving large regions of space almost devoid of galaxies. This process critically depends on the amount of dark matter and dark energy in the universe. To study the influence of dark energy on the process of formation of structure Demianski in collaboration with Ester Piedipalumbo from the Frederico Secondo University of Naples, Italy used the very distant gamma-ray bursts to study the expansion rate of the universe up to redshift of about 9. Results of their investigations were published in the Monthly Notices of the Royal Astronomical Society. In collaboration with A. Doroshkevich and S. Pilipenko from the Astro Space Center of the Russian Academy of Sciences in Moscow and S. Gotlloeber from the Astrophysical Institute in Potsdam, he analyzed evolution of the basic properties of simulated large scale structure elements formed by dark matter. The observed time dependence of the basic characteristics of structure elements and probability distributions supports the self-similar character of the process of structure formation. Results of this analysis were published recently in the Monthly Notices of the Royal Astronomical Society. In October 2010 Demianski participated in an international conference in Napoli where he delivered an invited talk “The Universe as a simple dynamical system.”

Kwitter continued her research into the chemical composition of planetary nebulae – the ejected shells of dying sun-like stars. These clouds, which contain results of nuclear processing inside the parent star, are valuable probes into the chemical enrichment of the Milky Way and other galaxies. Kwitter, Anne Jaskot’10 (now in graduate school at the University of Michigan), Dick Henry (University of Oklahoma) and Bruce Balick (University of Washington) completed their study of the oxygen abundance gradient in the Milky Way, concluding that uncertainties in distances, plus natural scatter in the oxygen abundances, leads to a final uncertainty in the gradient value that encompasses the range in the gradient that is predicted by different theorists; improvement will require better distances and a deeper understanding of the source of the scatter.

In the summer of 2010 Kwitter supervised three students: Connor Dempsey’13 and two students sponsored by KNAC, Vivienne Baldassare (Hunter’12) and Brian Kirk (Villanova’11). A large part of their summer was devoted to entering more than 10,000 emission line strengths and uncertainties for our sample of 164 planetary nebulae into a “master” spreadsheet. This spreadsheet is proving to be immensely valuable as they examine her sample of objects for trends and correlations that will help uncover physical underpinnings of observed behavior. Also, the students developed a morphological classification scheme to classify planetary nebulae according to their shapes and brightness characteristics. The classification is available, along with nebular images, at Bruce Balick’s Planetary Nebula Image Catalog site: http://www.astro.washington.edu/users/balick/PNIC/. These students accompanied Kwitter to a collaboration meeting with Henry and Balick at Apache Point Observatory in Sunspot, NM.

Kwitter, Henry and Balick (KHB) are now in the midst of studying planetary nebulae in the disk of M31, the Andromeda Galaxy. M31, located 2.5 million light-years away, is a twin to our own Milky Way. They obtained data for 16 planetary nebulae; Emma Lehman’10 participated in observing at the 8.1-meter Gemini-North telescope on Mauna Kea and in the data analysis. KHB have submitted proposals to use the Keck 10-meter telescope on Mauna Kea to observe 17 additional nebulae, which will help in defining M31’s oxygen gradient. KHB and additional colleagues have also submitted proposals to use the Hubble Space Telescope to observe planetary nebulae in both the Milky Way and M31 in the ultraviolet part of the spectrum to detect bright emission lines from the element carbon, which emits only feebly in the optical region. The ratios of carbon to nitrogen and to oxygen form important constraints on the evolution and nucleosynthesis inside planetary nebula parent stars stars. Finally, KHB and another set of colleagues have obtained spectra of H II regions (ionized gas clouds surrounding young stars) very near the center of the spiral galaxy M83, observed at McDonald Observatory of the University of Texas. Kwitter will determine the chemical composition in these regions, which are expected to be very metal-rich compared with the region in our Galaxy near the Sun.

In July Kwitter organized and attended the KNAC Faculty Meeting here at Williams; in November, she attended the KNAC Student Research Symposium at Colgate University. In January, she attended the 217th meeting of the American Astronomical Society (AAS) in Seattle, where she was a coauthor on three poster presentations; in April she gave a talk at the University of Washington in Seattle; also in April she spoke at the Midamerican Regional Astrophysics Conference in Kansas City; and in May she gave a talk at the Boston meeting of the American Astronomical Society. Finally, Kwitter was invited to give the review talk in on chemical abundances in planetary nebulae, “Cosmic Recycling: The Planetary Nebula Connection,” at the July 2011 Symposium #283 of the International Astronomical Union, with the theme Planetary Nebulae: An Eye to the Future.

Kwitter, who was on sabbatical for the academic year, presented the spring 2011 Sigma Xi Research Lecture on April 28, with a talk entitled, “Planetary Nebulae as Narrators of Stellar and Galactic Evolution.”

Pasachoff continued as Chair of the Working Group on Eclipses of the International Astronomical Union’s solar commissions and as a member of the Johannes Kepler Working Group of the History of Astronomy commission. He was elected Vice-Chair (2011-2014) and Chair-Elect (2014-2017) of the Historical Astronomy Division of the American Astronomical Society. He continues as U.S. National Liaison to Commission 46 on Education and Development of the International Astronomical Union, of which he is a past president. He is also head of the Program Group on Public Education at the Times of Eclipses and Transits of the Commission on Education and Development. See http://www.eclipses.info and http://www.transitofvenus.info. Pasachoff continues as representative of the AAS to the American Association for the Advancement of Science’s Astronomy Division, of which he was twice chair.

In July Pasachoff attended the KNAC Faculty Meeting at Williams. In January, he attended the 217th meeting of the AAS in Seattle and in May, he attended the 218th meeting in Boston. He attended the AAS Division of Planetary Sciences meeting in October in Pasadena and the Solar Physics Division’s meeting in June in Las Cruces, NM, presenting papers at each.

Pasachoff participated as on-campus thesis supervisor of the work of Sara Dwyer’11, with her thesis being a continuation of her KNAC Fellowship at Wesleyan under the guidance of Prof. William Herbst there. She worked on identifying stars and comparing star catalogues in the Orion Nebula region.

Pasachoff continued his K-12 education work with PROM/SE (Promoting Rigorous Outcomes in K-12 mathematics and Science Education), an NSF-funded organization based at Michigan State University. He attended their meetings in New York City in November and in Washington, DC, in June. (www.promse.msu.edu)

Pasachoff continues as astronomy consultant for the McGraw-Hill Encyclopedia of Science and Technology and its yearbooks. He also continues on the Physical Science Board of World Book. He is on the Council of Advisors of the Astronomy Education Review electronic journal. See http://aer.noao.edu/. Pasachoff continues as science book reviewer for The Key Reporter, the Phi Beta Kappa newsletter. He continues as advisor to the children’s magazine Odyssey, where he was guest editor of the May 2011 special issue about the Sun, to which he also contributed articles on eclipses and on transits of Venus.

Pasachoff was elected Fellow of the Society for Skeptical Inquiry. In a related course at Williams, he again gave his seminar on Science, Pseudoscience, and the Two Cultures in spring 2011.

Souza conducts the astronomy observing program, and all indoor labs and daytime observing. He hosted numerous observatory visitors, including planetarium groups, alumni, Family Days attendees, the Five College Astronomy Club, Summer Science Program students, the Massachusetts Teachers Association, and student previews and prospective students.

Souza continues to maintain and improve the observatory. He modified the control system of our 24″ telescope so that the camera software communicates with the telescope software. With Larry Mattison of the Science Shop, he motorized the shutter of the small dome of our widefield imaging system as a first step toward partial automation of the telescope. He acted as liaison with Wiliams’s Office of Information Technology, and worked with Facilities on maintenance issues.

Souza gave a guest lecture on Magnetic Resonance Imaging in CHEM 364. He attended the KNAC Faculty Meeting in July 2010 and the KNAC Student Symposium in September 2010. He also attended the American Astronomical Society (AAS) meetings in January 2011 (Seattle) and May 2010 (Boston).

In July 2010 Souza remotely observed an occultation of a star by Pluto, using a POETS system brought to a telescope in Santiago, Chile by Jay Pasachoff and students Muzhou Lu’13 and Craig Malamut (Wesleyan’12). In May 2011 he made, with Jay Pasachoff, Bryce Babcock, Matt Hosek’12, and Shubhanga Pandey’13, a similar observation of a Pluto occultation using POETS at our 24″ telescope in Williamstown.

Souza’s new research effort to monitor variations in H-alpha emission in massive stars continued in the summer of 2010, with Sarah Wilson’13 and Erin Boettcher (Haverford’12) working to evaluate the feasibility of the project and establish observing procedures. Matt Hosek’12 undertook a Winter Study 99 to develop a data-processing pipeline for the project. He presented the first publication resulting from this project as a poster at the Boston AAS meeting.

Class of 1960 Scholars in Astronomy

Sara M. K. Dwyer

Department Colloquia

[Colloquia are held jointly with the Physics Department. Listings can be found in the Physics section.]

Off-Campus Colloquia

Demianski, Marek

“The Universe as a simple dynamical system,”

International conference on The Universe as a Simple Mechnical System in Napoli, Italy, invited talk

October 2010

Karen B. Kwitter

“Abundances in Planetary Nebulae in M31, The Andromeda Galaxy”

Department of Astronomy, University of Washington, Seattle, WA

“Planetary Nebulae as a Teaching Tool”

41st Meeting of the Midamerican Regional Astrophysics Conference, Kansas City, MO

“Using Planetary Nebulae to Teach Physics”

in Special Session, Using Astronomy to Teach Physics, at the 218th meeting of the American Astronomical Society, Boston, MA

Olson, Roberta J. M., and Jay M. Pasachoff

“The Comets of Caroline Herschel (1750-1848), Sleuth of the Skies at Slough”

The Inspiration of Astronomical Phenomena VII (insap.org), Bath (2010)

Pasachoff, Jay M., and Roberta J. M. Olson,

“Report of Some Comets: The Discovery of Uranus and Comets by William, Caroline, and John Herschel”

217th meeting of the American Astronomical Society meeting, Seattle, January 2011

Pasachoff, J.M., Elliot, J.L., Souza, S.P., Person, M.J., Zuluaga, C., Bosh, A.S., Zangari, A.M.,

Jensen-Clem, R., Lockhart, M., Gulbis, A.A.S., Rojo, P., Lu, M., Malamut, C., Ng_Tam, Y.H.,

Levine, S., Ivarsen, K.M., Reichart, D.E., LaCluyze, A.P., Nysewander, M.C., Haislip, J.B.,

MacDonald, R.K.D., Bailyn, C.D., Rabinowitz, D., Emilio, M., Jehin, E., Gillon , M.,

Manfroid, J., Chantry, V., Magain, P. Hutsemekers, D., and Queloz, D

“The 3 / 4 July 2010 Pluto Stellar-Occultation Observations”

42nd Meeting, Division for Planetary Sciences, American Astronomical Society

Pasadena, October 2010

Pasachoff, Jay M., B. A. Babcock, J. L. Elliot, M. J. Person, A. A. S. Gulbis, C. Zuluaga, A. Zangari, W. Rosing, F. Bianco, J. E. Ciotti, S. W. L. Plunkett, Jr., M. R. Kessler, N. D. Niraoka, K. Mohanan, E. Pilger, T. George, D. Breit, S. Preston, K. Lonergan, S. Menaker, J. Egger, M. Lockhart, M. Gutoski, P. Rulon, D. Hampton, X. Jiang, J. Bai, W. P. Chen, M. Lehner, N. Tokimasa

“”Attempted Stellar-Occultation Observations for KBO (20000) Varuna on February 10 2011”

218th meeting of the American Astronomical Society meeting, Boston, May 2011

Pasachoff, Jay M., Michael E. Brown (Caltech), Michael J. Person (MIT), and Yung Hsien Ng Tam’12

“Pluto and Beyond: Stellar-Occultation Web Pages for Education and Observation Planning,”

Pasadena meeting of the Division of Planetary Sciences, American Astronomical Society, 2010

Person, M.J., Elliot, J.L., Bosh, A.S., Gulbis, A.A.S., Jensen-Clem, R., Lockhart, M.F.,

Zangari, A.M., Zuluaga, C., Levine, S.E., Pasachoff, J.M., Souza, S.P., Lu, M., Malamut, C.,

Rojo, P., Bailyn, C.D., Rabinowitz, D., MacDonald, R.K.D., Ivarsen, K.M., Reichart, D.E.,

LaCluyze, A.P., Nysewander, M.C., and Haislip, J.B

“Pluto’s Atmosphere from the July 2010 Stellar Occultation”

42nd Meeting, Division for Planetary Sciences, American Astronomical Society

Pasadena, October 2010

Elliot, J.L., Person, M.J., Zuluaga, C.A., Bosh, A.S., Adams, E.R., Brothers, T.C.,

Gulbis, A.A.S., Levine, S.E., Lockhart, M., Zangari, A.M., Babcock, B.A., DuPré, K.,

Pasachoff, J.M., Souza, S.P., Rosing, W. and Secrest, N.

“Size and albedo of Kuiper belt object 55636″

42nd Meeting, Division for Planetary Sciences, American Astronomical Society

Pasadena, October 2010

Rebecca Jensen-Clem, J. L. Elliot, M. J. Person, C. A. Zuluaga, A. S. Bosh, E. R. Adams,

T. C. Brothers, A. A. S. Gulbis, S. E. Levine, M. Lockhart, A. M. Zangari, B. A. Babcock,

K. DuPre, J. M. Pasachoff, S. P. Souza, W. Rosing, N. Secrest, L. Bright, E. W. Dunham,

M. Kakkala, T. Tilleman, S. Rapoport, L. Zambrano-Marin, J. Wolf, and K. Morzinski

“A Search for Satellites of Kuiper Belt Object 55636 from the 2009 October 9 Occultations”

217th Meeting of the American Astronomical Society

Seattle, WA, January 2011

Pasachoff, Jay M.

“The Sun and Solar Eclipsea,”

Sydney Observatory, Australia, December 2010

“Solar Eclipses Linked with Space Observations”

Royal Observatory of Belgium, Brussels, February 2011

“Transits of Venus and Mercury,”

Observatoire de Paris, March 2011

“The Sun and Solar Eclipses”

Amateur Astronomical Society of Seltjarnrnes, University of Iceland, May 2011

S. P. Souza, E. Boettcher, S. Wilson, and M. Hosek

“Hα Monitoring of Early-Type Emission Line Stars”

218th Meeting of the American Astronomical Society, Boston, MA, May 2011

Postgraduate Plans of Department Majors