Experience

Contact Information

Office:  TPL 110
Phone:  (413) 597-2272
FAX:     (413) 597-3200
E-mail: kkwitter-at-williams.edu (replace -at- with @)

In the fall, I regularly teach the introductory astrophysics course for potential majors, Astronomy 111, "Introduction to Astrophysics," which concentrates on stellar evolution as the laboratory for exploration into astrophysical ideas.

In the fall of 2008, I will again teach Astronomy 207T, "Extraterrestrial Life in the Galaxy: A Sure Thing or a Snowball's Chance?," a tutorial on the search for extraterrestrial life in the Galaxy. Among our topics, we discuss the formation of life on Earth, conditions elsewhere in the solar system that might be suitable, planets around other stars, and the ongoing search for radio and optical signals from extraterrestrial civilizations.

I also teach Astronomy 211, "Observation and Data Reduction Techniques in Astronomy," a course on the techniques and technology of modern astronomical observing. Students will learn how to plan, carry out, reduce and analyze real astronomical data using our 24-inch telescope, CCD detectors, and other equipment on our observing deck.

In the fall of 2006, I offered a new tutorial, Astronomy 219T/419T, "Observational Cosmology," for sophomores, junior and seniors. Every time cosmology is taught there is new material to talk about, with the latest observations, experiments and theories. I will likely teach this again in a couple of years.

In the spring, I occasionally offer Astronomy 330, "The Nature of the Universe," a junior/senior non-majors course on cosmology. With a little bit of algebra and perseverance, non-specialists can understand a surprising amount of cosmological material. This is a fascinating time to be learning cosmology, given the exciting recent measurements pinpointing the age of the Universe and its current rate of expansion, as well as new discoveries and theories of why the Universe behaves as it does.

I have developed a course in my research area, Astronomy 402, "Between the Stars: The Interstellar Medium," a seminar on the interstellar medium, which I taught last in the spring of 2008. In this upper-level class we do lots of observing and computer work to explore the various manifestations of matter between the stars and the physical mechanisms that produce them.

Combining teaching and research interests, my colleague R. Henry and I have developed a Gallery of Planetary Nebula Spectra, presenting spectra of more than 120 objects we have observed over the years in a browsable format that also contains a zoomable spectrum display. The site contains atlas information for all the objects and links to images. Several exercises designed to help explore the data are also available.

Research Interests

My research centers on planetary nebulae: glowing gas shells ejected by low- to intermediate-mass stars near the end of their lives. Planetary nebulae represent a treasure trove of information about stellar evolution, nucleosynthesis and environment. Their chemical compositions, central stars, morphology and origin have been the focus of my work. Astronomy students have participated extensively in all aspects of my research, joining my colleagues and me on observing trips as well as working on campus over the summer and writing senior honors theses.

CURRENT WORK
My work focuses on chemical abundances in planetary nebulae as a means to understand the formation history of the Milky Way Galaxy and M31 (the Andromeda Galaxy, our neighbor and sibling), concentrating on the lowest-metallicity regions in the outskirts of both galaxies. This is an ambitious undertaking that requires identifying and obtaining spectra for newfound planetaries in both galaxies. My main collaborators are Prof. Richard Henry from U. Oklahoma and Prof. Bruce Balick from U. Washington. Our entire team, which includes astronomers (and students) from institutions in the United States, Great Britain, and Italy, has just (May 2008) been awarded a three-year National Science Foundation grant for this work. The following paragraphs describe ongoing components of this larger project.

Planetary Nebulae in the Galactic Anticenter and the Andromeda Galaxy
In the summer of 2006, we began to study the abundances of planetary nebulae in the outerdisk of the Milky Way Galaxy as well as in the halo of the Andromeda Galaxy. We have been obtaining spectra of planetary nebulae in these regions using the 3.6-meter telescope at Apache Point Observatory in New Mexico (which we operate remotely via the web from the Williams campus!). Anne Jaskot '08 worked on this project for her senior honors thesis. In addition, she travelled to Chile to observe at Cerro Tololo Interamerican Observatory with Prof. Frank Winkler of Middlebury College, with whom we are collaborating on a study of planetary nebulae in the Small Magellanic Cloud, one of the Milky Way's many satellite galaxies.

Chemical Abundance Patterns in Galactic Planetary Nebulae
Dick Henry and I study the abundance patterns of important chemical elements in planetary nebulae. Here we are with colleague Jackie Milingo, now at Gettysburg College. Recently we have been concentrating on the abundances of oxygen and nitrogen in "Type I" planetary nebulae - those that originate from the most massive parent stars - to see if there is systematic evidence of oxygen depletion, which is expected if a certain sequence of nuclear reactions has taken place in the star's core. Dr. Steven Souza from our department joined in this effort. In the summer of 2007, Cliff Harvey (Worcester Polytech '08; Keck Northeast Astronomy Consortium exchange student) worked on infrared spectra of two planetary nebulae in the halo of the Milky Way, obtained with the Infrared Spectrograph aboard the Spitzer Space Telescope. Such spectra allow us to measure the intensities of emission lines from ions not detectable with optical spectra, thereby aiding our determinations of the nebula's chemical composition.

The Sulfur Anomaly
Dick Henry and I have also been exploring the abundances of sulfur, argon and chlorine in planetary nebulae. In the stellar mass range that produces planetary nebulae, the abundances of these elements are not expected to be affected by the nuclear processing that drives changes in the carbon, helium, and nitrogen abundances during billions of years of stellar evolution. So by studying sulfur, argon and chlorine in planetary nebulae now, we have the exciting prospect of investigating the chemical evolution of the Galaxy over time, analogous to the use of the iron abundance to track Galactic chemical evolution in stars. In 1999 we received an NSF grant to pursue this work and made observations at Kitt Peak and Cerro Tololo, in which students participated. Jackie Milingo and Bruce Balick participated in portions of this work. We have discovered and are investigating an unexpected, systematic deficit in the sulfur abundance as the oxygen abundance increaseswe have called this the "sulfur anomaly" - see the paper entitled "Sulfur, Chlorine and Argon Abundances in Planetary Nebulae. IV. Synthesis and the Sulfur Anomaly" below.

In the summer of 2003, Davy Stevenson '04, Lissa Ong '05, and Megan Roscioli (Haverford '05; Keck Northeast Astronomy Consortium exchange student) worked with me to reduce and analyze spectra. Part of this work constituted Stevenson's honors thesis.

ELSA: A Package for Spectrum Analysis
In the summer of 2005 Jesse Levitt '08 and Matthew Johnson (Wesleyan '07; Keck Northeast Astronomy Consortium exchange student) worked on updating and automating a computer code written by R. Henry that calculates nebular conditions and abundances from measured spectroscopic data. In addition to being co-authors on the resulting paper, Jesse and Matt presented their work at a January 2006 meeting of the American Astronomical Society in Washington, D.C. and at an April 2006 symposium on planetary nebulae sponsored by the International Astronomical Union in Waikoloa, Hawaii. Here we are at the IAU. A paper on this program, called ELSA, will shortly be submitted, with Matt and Jesse as the first authors.

During the summer of 2006, two students, Jesse Levitt '08 and Peter O'Malley (Haverford '08; Keck Northeast Astronomy Consortium exchange student) upgraded ELSA. Here we are during a mini-conference in July 2006, when Dick Henry and Matt Johnson both came to campus. Jesse also worked on ELSA in the summer of 2007. And, here are ELSA folks at the 2007 KNAC Student Research Symposium held at Williams in September.

Carbon Abundances in Galactic Planetary Nebulae and Extragalactic H II Regions
Beginning in the fall of 2003, I started working with colleagues R. Henry and Prof. Reginald Dufour (Rice U.) on a project with the Hubble Space Telescope to obtain images of planetary nebulae and H II regions in the Milky Way and other galaxies, in order to study the abundance of carbon in these gas clouds; we received time in Cycle 12 and again in Cycle 15 to carry out these observations. During the summer of 2004, Joseph Gangestad '06 worked on analysis of archived ultraviolet spectra taken with the IUE spacecraft.

Past Projects
Carbon Abundances in Galactic Planetary Nebulae
R. Henry and I had earlier investigated production of carbon as a function of stellar mass and metallicity by stars that eventually produce planetary nebulae. This project included use of archived ultraviolet spectra from the IUE satellite, optical observations from the 2.1 meter telescope at Kitt Peak, the 1.5 meter telescope at Cerro Tololo, as well as computer modeling of the nebulae and the evolution of their central stars.

Imaging Haloes of Planetary Nebulae
During the 1990's, with colleagues Prof. You-Hua Chu ( U. Illinois) and Dr. Ronald Downes (STScI), I obtained large-field CCD images with the Burrell-Schmidt telescope at Kitt Peak, and discovered halos around several planetaries. (Click here to see long-exposure images of M27, the Dumbbell Nebula or NGC 7293, the Helix Nebula.) The gossamer-like outer shells testify to the history of stellar wind and ejection of envelope material from the star all during its history. Most recently, the National Optical Astronomy Observatories issued a press release highlighting our images of Owl Nebula.

Also in the 1990's, Dr. Richard Tweedy and I discovered possible planetary nebulae around hot white dwarf stars, and also investigated the interaction of old planetary nebulae and the interstellar medium. This latter project culminated in the publication of an extensive atlas presenting deep images of ancient planetary nebulae testifying to substantial interaction. Here is a sample of the images in the atlas.

Other examples of student research participation:
In the summer of 2002, Matthew Hoffman '04 and Mun Chan (Middlebury '03; Keck Northeast Astronomy Consortium exchange student) accompanied me to KPNO to observe several planetary nebulae with the echelle spectrograph on the 4-meter telescope.

In the summer of 2001, Roger Cohen (Wesleyan '03; Keck Northeast Astronomy Consortium exchange student) worked with me to calculate and assemble abundances of sulfur, argon and chlorine in 45 southern planetary nebulae. The resulting paper, on which Roger is a co-author, was published in the Astrophysical Journal Supplement (see below).

In the summer of 2000, Gabe Brammer '02 and Sun Mi Chung (Wesleyan '02; Keck Northeast Astronomy Consortium exchange student) worked on spectra to investigate gradients in physical conditions and abundances in planetary nebulae.

In the summer of 1999, Joel Iams '01 and Hugh Crowl (Wesleyan '00; Keck Northeast Astronomy Consortium exchange student) came to Kitt Peak National Observatory with me to observe with the 2.1 meter telescope. Iams and Crowl, along with Leila Zelnick '00 worked with me to analyze the data.

Selected Publications

• The Chemical Composition and Origin of the Wolf-Rayet Ring Nebula NGC 6888, Kwitter, K.B., Ap.J., 245, 154, 1981.
  
  
• The Relation Between Radius and Expansion Velocity in Planetary Nebulae, Chu, Y.-H., Kwitter, K.B., Kaler, J.B., and Jacoby, G.H., Publ. Astr. Soc. Pac., 96, 598, 1984.
  
  
• Identification of Faint Central Stars in Extended, Low Surface Brightness Planetary Nebulae, Kwitter, K.B., Jacoby, G.H., and Lydon, T.J. (Williams '86), A.J., 96, 997, 1988.
  
  
• Large Planetary Nebulae and Their Significance to the Late Stages of Stellar Evolution, Kaler, J.B., Shaw, R.A., and Kwitter, K.B., Ap. J., 359, 392, 1990.
  
  
• The Ionization Structure of Old Planetary Nebulae Which Interact with the Interstellar Medium, Tweedy, R. W., and Kwitter, K.B., A.J., 108, 188, 1994.
  
  
• A New Look at Carbon Abundances in Planetary Nebulae: I. PB6, Hu2-1, K648, and H4-1, Henry, R.B.C., Kwitter, K.B., and Howard, J.W., Ap.J., 458, 291, 1996.
  
  
• A New Look at Carbon Abundances in Planetary Nebulae: II. BB-1, NGC 650, NGC 1535, NGC 2440, & NGC 7027, Kwitter, K.B., and Henry, R.B.C., Ap.J., 472, 304, 1996.
  
  
• An Atlas of Ancient Planetary Nebulae and Their Interaction with the ISM, Tweedy, R.W., and Kwitter, K.B., Ap.J. Suppl., 107, 1996.
  
  
• A New Look at Carbon Abundances in Planetary Nebulae: III. DDDM1, IC 3568, IC 4593, NGC 6210, NGC 6720, NGC 6826, & NGC 7009, Kwitter, K.B., and Henry, R.B.C., Ap.J., 493, 247, 1998.
  
  
• The Planetary Nebulae in NGC 6441 and Pal 6, Jacoby, G.H., Fullton, L.K., Morse, J., Kwitter, K.B., & Henry, R.B.C., A.J., 114, 2611, 1998.
  
  
• Morphology and Composition of the Helix Nebula, Henry, R.B.C, Kwitter, K.B., & Dufour, R.J., Ap.J., 517, 767, 1999.
  
  
• A New Look at Carbon Abundances in Planetary Nebulae: IV. Implications for Stellar Nucleosynthesis, Henry, R.B.C., Kwitter, K.B., & Bates, J.A. (Williams '98), Ap.J., 531, 928, 2000.
  
  
• Sulfur, Chlorine and Argon Abundances in Planetary Nebulae. I. Observations and Abundances in a Northern Sample, Kwitter, K.B., & Henry, R.B.C. Ap.J., 562, 804, 2001.
  
  
• Sulfur, Chlorine and Argon Abundances in Planetary Nebulae. IIA. Observations of a Southern Sample, Milingo, J.B., Kwitter, K.B., Henry, R.B.C., & Cohen, R.E. (Wesleyan '03) Ap.J.Suppl., 138, 279, 2002.
  
  
• Sulfur, Chlorine and Argon Abundances in Planetary Nebulae. IIB. Abundances in a Southern sample, Milingo, J.B., Henry, R.B.C., & Kwitter, K.B., Ap.J. Suppl., 138, 285, 2002.
  
  
• Sulfur, Chlorine and Argon Abundances in Planetary Nebulae. III. Observations and Results for a Final Sample, Kwitter, K.B., Henry, R.B.C., & Milingo, J.B., Pub. Astr. Soc. Pac., 115, 80. 2003.
  
  
• Sulfur, Chlorine and Argon Abundances in Planetary Nebulae. IV. Synthesis and the Sulfur Anomaly, Henry, R.B.C., Kwitter, K.B., & Balick, B., Astron.J., 127, 2284, 2004.
  
  
• The Shaping of Planetary Nebula Sh2-188 through Interaction with the Interstellar Medium, Wareing, C.J., O'Brien, T.J., Zijlstra, A., Kwitter, K.B., Irwin, J., Wright, N., Greimel, R., & Drew, J.E., Mon. Not. R.A.S., 366, 387, 2006.
  
  
• A Multiwavelength Analysis of the Halo Planetary Nebula DdDm-1, Henry, R.B.C., Kwitter, Dufour, R. J. & Skinner, J. N., Ap.J., 680, 1162, 2008.
  
  

Books

Earth Science: Exploring Earth and Space, K. Kwitter, D. Roberts, & B. Zimmerman 1992, Globe Book Co. - a junior high school text.

Atmosphere and Weather, K. Kwitter & S. Souza, 1998.
Force and Motion, S. Souza & K. Kwitter, 1999.
The Solar System, S. Souza & K. Kwitter, 1999.

These are three books in the "Hands-On Science" activity series published by J. Weston Walch for junior high and high school students. These were written with Steven Souza, who is now Observatory Supervisor and Instructor in the Astronomy Department.

Recent Professional Service

• Member, Observatories Council of Associated Universities for Research in Astronomy (AURA), 2002-2005; 2005-2008.
• Committee on the Status of Women of the American Astronomical Society, 2000-2003 (also 1982-1985); liaison with the Astronomy Education Board.
  
• Annie J. Cannon Selection Committee of the American Astronomical Society, 1999-2002; Chair, 2002.
  
  

Non-Science Stuff

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