Department of Physics

Julie Ziffer Ph.D.

Professor of Physics

Office Location

Science Building 227, Portland



Academic Degrees

  • Ph.D. University of Central Florida


“Through my research into the composition of asteroids and comets, I’m looking for clues to the conditions that prevailed before our solar nebula formed. In the physics classroom and in the lab, our students are exploring one of the big mysteries of astronomy: understanding the process of planet formation–and the origins of life on Earth.”

- Julie Ziffer, Assistant Professor of Physics


Academic Degrees
Ph.D., University of Central Florida, 2006
B.S., Truman State University, 1994

Somewhere between Mars and Jupiter, approximately 400 million kilometers from the Sun, there is an asteroid with Julie Ziffer’s name on it. Dr. Ziffer earned this rare honor from the International Astronomical Union (IAU) in recognition for her role in unraveling one of astronomy’s great science: how did life begin on Earth?

Dr. Ziffer was part of two international teams of scientists investigating the composition of asteroid 24 Themis. This group determined that 24 Themis contained organic materials and, surprisingly, ice deposits spread across its surface. “Our work has provided some of the first real evidence that, in addition to organic matter, asteroids can hold reservoirs of water, supporting the theory that these life ingredients were delivered to Earth through collisions with asteroids and comets.”

Her focus as a researcher is to analyze the surface characteristics of primitive solar system objects via photometry and spectroscopy in hopes of determining their formation environment and evolutionary processes. “These are compelling objects for study because, being relatively unprocessed, they provide clues to the conditions that prevailed before our solar nebula formed.” And there are practical reasons: “Approximately 10% of the Near-Earth-Object (NEO) population is of cometary origin. It is important to know the composition of these objects to assess the severity of a possible impact with Earth.”

A member of the Physics faculty, Dr. Ziffer teaches astronomy and physics courses and provides exciting opportunities for undergraduates through her research projects. She considers research a cooperative endeavor where collaborations and full integration into the research community is essential. Her current research priority is on near-infrared spectroscopy and photometry of unprocessed objects such as asteroid families, primitive Main-Belt and Trojan asteroids, and dormant comet candidates. This work utilizes data obtained from NASA’s premier Infrared Space Telescope (Spitzer), NASA’s dedicated ground-based Infrared Telescope Facility (IRTF), NASA’s Wide-Field Infrared Survey Explorer, and the Wyoming Infrared Observatory. 

Media links: (video)

Research Interests

Composition of asteroids and comets

Recent Publications

Campins, H.,  Deleon, J., Licandro, J.,   Kelley, M.,  Fernández, Y., Ziffer, J.,  Nesvorny, D. 2012.  Spectra of asteroid families in support of Gaia.  Accepted: Planetary and Space Science. 

Licandro, J., Hargrove, K.,  Kelley, M., Campins, H., Ziffer, J., Alí-Lagoa, V.,  Fernández, Y., Rivkin, A., 2012. 5-14 μm Spitzer spectra of Themis family asteroids. A&A  vol. 537 pp. 73. 

International Outer PLANET Watch Team (Iopw-Pvol) Sánchez-Lavega et al.  2011. Long-term evolution of the aerosol debris cloud produced by the 2009 impact on Jupiter. Icarus vol. 214 pp. 462. 

Ziffer, J., Campins, H., Licandro, J., Walker, M. E., Fernandez, Y. R., Clark, B. E., Mothe-Diniz, T., Howell E., and Deshpande, R. 2011. Near-Infrared Spectroscopy of Primitive Asteroid Families. Icarus.Volume 213, Issue 2, p. 538-546. 

Meech, K., and 192 Coauthors. 2011. EPOXI: 103P/Hartley 2 Observations From a Worldwide Campaign. ApJ Letters. Volume 734, Issue 1

Clark B. E., Ziffer, J., Nesvorny, D. , Campins, H., Rivkin, A. S., Hiroi, T., Barucci, M. A., Fulchignoni, M. Binzel, R.,  Fornasier, S., DeMeo, F., Ockert-Bell, M. E., Licandro, J., and Mothe-Diniz, T. 2010 Spectroscopy of B-type asteroids: Subgroups and meteorite analogs.  Journal of Geophysical Research.  Volume 115, p. 6005. 

Campins, H.,  Hargrove, K.,  Pinilla-Alonso, N.,  Howell, E.S., Kelley, M.S., Licandro,J., Mothé-Diniz, T., Fernandez, Y., and Ziffer, J. , 2010 Ice And Organics On Asteroid 24 Themis: A Possible Link To The Origin Of Earth's Water. Nature.  Volume 464, pp.1320-1321.

Fernández, Y. R.,  Jewitt, D., and Ziffer, J. E.,  2009. Albedos of  Small Jovian Trojans. The Astronomical Journal, Volume 138, Issue 1, pp. 240-250.

Campins, H., Licandro, J., Pinilla-Alonso, N., Ziffer, J., de León, J., and Mothé-Diniz, T. 2007. Nuclear Spectra of Comet 28P Neujmin 1.  Astronomical Journal, Volume 134, Issue 4, pp. 1626-1633.