Affiliate of the
NASA Johnson Space Center
Planetary Astronomy Group

Professor Susan Lederer
Department of Physics
California State University San Bernardino
Office: PS-111
slederer@csusb.edu
909-537-5389 (phone)
909-537-5298 (fax)

EDUCATION

Ph.D. in Astronomy, University of Florida

Thesis: The Chemical and Physical Properties of the
OH, CN and C2 Jets in Comet Hale-Bopp (1995 O1)

M.S. in Astronomy, New Mexico State University

Thesis: Consequences of Albedo Feature Inhomogeneities
for Jovian Seismology

B.S. in Physics and Mathematics, University of Wisconsin Eau Claire

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TEACHING

 

COURSES for 2008/9:

Textbook Information for 2008/9 school year

 

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RESEARCH

Undergraduate Research Position may be available in Planetary Science

Dr. Lederer has an active planetary science research program established.  She spends her summers and most breaks at NASA Johnson Space Center in Houston, TX. Her most recent project is in collaboration with Dr. Mark Cintala, Director of the Experimental Impact Laboratory, and Dr. Keiko Nakamura-Messenger, Dr. Lindsay Keller, and Dr. Michael Zolensky in the ARES division of NASA Johnson Space Center. She also collaborates with Dr. Faith Vilas, director of the MMT Observatory and her advisor while a National Research Council Postdoctoral Research Associate at NASA JSC. She has maintained the connections she formed with the NASA JSC Planetary Astronomy Group (PAG). A NASA MUCERPI grant and Research Corporation Cottrell College Scholarship has allowed her to both hire students to work on research during the school year, and regularly bring students to Houston to work with the PAG.  Students have actually found summer temperatures in Houston to be more pleasant than in the Inland Empire, much to the amazement of many. They really enjoy their experiences and being surrounded by NASA’s space program.

Dr. Lederer regularly travels to observatories to collect ground-based data, and brings students along to take part in the observing runs.   She recently began a new project investigating how the properties of comets and comet dust changes when these objects experience collisions in the Solar system by conducting laboratory impact experiments. She has also been involved in projects involving the space-based Spitzer Infrared Observatory.  An astronomer by nature (not just profession), she thrives on staying up all night long to collect ground-based data at places such as Lowell Observatory (Flagstaff, AZ), Las Campanas (Chile, South America), Kitt Peak (Tucson, AZ), and the IRTF (NASA's Infrared Telescope Facility; Mauna Kea, Hawaii).  She also appreciates that planetary scientists schedule important meetings in strategically beautiful places in the US and all over the world.

Research interests:
Dr. Lederer is currently working on research involving comets, asteroids, Kuiper Belt Objects and Centaurs. Other research has included icy satellites, Mercury, and Jupiter. Current projects include:

  • Hypervelocity impact experiments of materials found in comet:

 NASA Johnson Space Center’s Experimental Impact Laboratory houses three guns designed to simulate impacts into planetary bodies. In 2007, we began a new project to investigate how collisions comets experience might affect the surface properties of comets and the petrology and mineralogy of the dust. To accomplish this, minerals and icy composites that represent the composition of comet dust and nuclei are impacted. Both the Vertical Impact Facility (accelerating projectiles to 2-3km/s) and the Light Gas gun (3-7km/s) are used for these experiments. The targets are place in a vacuum chamber, impacted, and then analyzed using instruments such as a Fourier Transform Infrared Spectrometer and a Transmission Electron Microscope.

  • Investigating the surface properties of the near-Earth asteroid (NEA) 25143 Itokawa:

This NEA will be visted by the Japanese spacecraft called Hayabusa (formerly called MUSES-C) in the fall of 2005. She is a member of the Near-Infrared Spectrometer (NIRS) team. NIRS is an instrument on board this spacecraft.  She presented research results at the First Hayabusa International Symposium in Japan in October, 2004. These ongoing studies began in 2001. We collected a vast amount of additional data at Lowell Observatory in Flagstaff, Arizona during the winter of 2004, and at the Las Campanas Observatory in Chile, South America during the summer of 2004 when the asteroid was at favorable viewing geometries to extend our analysis with Hapke modeling. Hapke models allow us to investigate the surface properties of the asteroid, such as the single particle scattering properties, geometric and bond albedos, and the forward and backward scattering properties of the surface. This project is in collaboration with Dr. Faith Vilas at NASA Johnson Space Center, Dr. Deborah Domingue at the Johns Hopkins University Applied Physics Lab, and Drs. Joanna Thomas-Osip and Dave Osip at the Las Campanas Observatory in Chile.

  • Deep Impact Ground-based observing support:

In July, 2005, the Deep Impact Spacecraft  rendezvoused with Comet Tempel 1, and successfully fired a projectile to impact with the comet. Dr. Lederer returned to the Las Campanas Observatory in Chile to collect ground-based data of the comet before and after the impact. In collaboration with Dr. Jim DeBuizer, Dr. Dave Osip, Dr. Joanna Thomas-Osip, and Dr. Kaspar Von Braun, Dr. Lederer is analyzing visible band images she collected with the 2-meter Dupont telescope, employing narrowband comet filters. Data was also collected with the 8-meter CTIO Gemini South telescope with the OSCIR mid-infrared camera and spectrometer instrument, and the twin LCO Magellan telescopes. Additional data were collected with these telescopes at Las Campanas Observatory in Chile before, during, and after the impact.

  • Mineralogy of Comet Dust:

The Spitzer space telescope is an infrared telescope that was launched into space to orbit the Earth in August, 2003. Dr. Lederer is a co-Investigator on 2 cycle-1 proposals that were selected to study the properties of dust in the coma of both Jupiter family (short period) comets, as well as Oort Cloud (long period) comets. Additional proposals have been submitted to continue these studies during Cycle-2.  By studying the infrared spectra of these comets (See Comet Hale-Bopp and Tempel 1 spectra collected by C.M. Lisse for an example), we will investigate the composition and physical properties (such as temperature) of these grains. The grains we are studying may be the source of gas jets observed in cometary coma (see Comet Hale-Bopp project below).  These projects are in collaboration with Dr. Diane Wooden at NASA Ames Research Center, and Dr. Chick Woodward at the University of Minnesota, and include scientists in Europe as well as the US.

  • Investigating the properties of gas jets seen in the comae of comets:

In particular, Comet Hale-Bopp showed gas jets in OH, CN, C2, C3, and NH.  Modeling these gas jets (the OH, CN and C2 jets in particular) with Monte Carlo models gives us information about where the jets might originate from active areas on the surface and the sources of the gases (molecular gas parent versus extended source grain parent). We found that while much of the gases observed originate from molecules released directly from the nucleus, the gas jets originate from a non-nuclear source. This source is likely the very tiny, hot sub-micron organic grains, composed of Carbon, Hydrogen, Oxygen and Nitrogen (CHON grains), and the gases we observed as gas jets in the coma likely thermally dissociated from the grains as the grains were swept into the coma of this comet. This work is in collaboration with Dr. Humberto Campins at the University of Central Florida.

  • Studying the chemical and physical properties of Kuiper Belt Objects and Centaurs:

Kuiper Belt Objects  are comets that exist in a belt beyond Neptune's orbit, and Centaurs are believed to be transitioning from the Kuiper Belt into the inner solar system. Broadband colors can yield information about the chemical properties and their evolution over time. Part of this work was designed to search for a broad, shallow 0.7 mm absorption feature that would suggest that these objects have undergone aqueous alteration, similar to C-class asteroids. Aqueous alteration is the chemical alteration of materials at low temperatures by liquid water that produces minerals such as oxides, hydroxides, sulfates, and phyllosilicates. The 0.7 mm absorption feature has been attributed to oxidized iron present in phyllosilicates by work completed by Dr.  Vilas. This work is in collaboration with Dr. Faith Vilas at NASA Johnson Space Center.

 

Just for fun:

Asteroid 19017 Susanlederer (2000 RH93) is a Main-belt asteroid discovered (appropriately) by LONEOS, the Lowell Observatory Near-Earth Object Survey… appropriately since Dr. Lederer collected all of her Ph.D. thesis data of Comet Hale-Bopp and much of her research data of comets, asteroids, and KBOs at Lowell Observatory, since then. This asteroid was discovered on Sept 4, 2000, the same month Dr. Lederer defended her Ph.D. thesis. The asteroid has an orbital period of 4.93 y,  a low eccentricity (0.03), and its average distance from the Sun (the orbital semi-major axis) is 2.9 AU.

Recent Refereed Publications:
For a full listing of papers and abstracts, click here.

*      Lederer S.M., H. Campins, and D.J. Osip. submitted. Chemical and physical properties of gas jets in comets: I. Modeling OH, CN and C2 jets in Comet C/1995 O1 (Hale-Bopp) one month after perihelion.  Icarus.

*      Lederer S.M., H. Campins, and D.J. Osip. submitted. Chemical and physical properties of gas jets in comets: II. Monte Carlo model of an inner cometary coma.  Icarus.

*      Lederer S. M., C M.J. Cintala, R. D. Olney,  L.P. Keller, K. Nakamura-Messenger, M.E. Zolensky 2008. Collisional Processing of Olivine and Pyroxene in Cometary Dust. Lunar Pl. Sci. Conf. 39, 2316.

*      K. Kitazato, B.E. Clark, M. Abe, S. Abe, Y. Takagi, T. Hiroi, O.S. Barnouin-Jha, P.A. Abell, S.M. Lederer, and F. Vilas, 2008. Near-Infrared Spectrophotometry of Asteroid 25143 Itokawa from NIRS on Hayabusa Spacecraft.  Icarus 194, 137-145.

*      Shepard, M.K., B.E. Clark, M.C. Nolan, L.A.M. Benner, S.J. Ostro, J.D. Giorgini, F. Vilas, K. Jarvis, S. Lederer, L. Lim, T. McConnichie, J. Bell, J.L. Margot, A. Rivkin, P. Pravec. 2008. Multi-wavelength observations of asteroid 2100 Ra-Shalom. Icarus 193, 20-38.

*      J.E. Thomas-Osip, S.M. Lederer, D. Osip, F. Vilas, D. Domingue, K. Jarvis, S.L. Leeds. 2008. The 2004 Las Campanas/Lowell Observatory Campaign I. Simultaneous Visible and near-Infrared Photometry of Hayabusa Target asteroid 25143 Itokawa. Earth, Planets and Space 60, 39-48.

*      S.M. Lederer, F. Vilas, J.E. Thomas-Osip, D.L. Domingue, D.J. Osip, K.Jarvis and S.L. Leeds. 2008. The 2004 Las Campanas/Lowell Observatory Campaign II. Surface Properties of Hayabusa target asteroid 25143 Itokawa Inferred from Hapke Modeling.  Earth, Planets and Space 60, 49-59.

*      M.S. Kelley, C.E. Woodward, D.E. Harker, W.T. Reach, D.H. Wooden, R.D. Gehrz, H. Campins, M.S. Hanner, S.M. Lederer, D.J. Osip, J. Pittichova, and E. Polomski. 2006. The Dust Properties of Comets 2P/Encke, 67P/Churyumov-Gerasimenko, and C/2001 HT50 (LINEAR-NEAT) from Mid-Infrared Spectroscopy 2006. Astrophys. J. 651, Issue 2, 1256-1271.

*      Abe M., Y. Takagi, K. Kitazato, S. Abe, T. Hiroi, F. Vilas, B.E. Clark, P.A. Abell, S.M. Lederer, K.S. Jarvis, T. Nimura, Y. Ueda, and A. Fujiwara. 2006. Near infrared spectral results of the Hayabusa mission at asteroid Itokawa. Science 312, Issue 5778, 1334-1338.

*      Meech K.J., +208 authors, including S.M. Lederer. 2005. Deep Impact: Observations from a Worldwide Earth-Based Campaign. Science 310, Issue 5746, 265-269.

*      F. Vilas, S.M. Lederer, S.L. Gill, K.S. Jarvis, and J.E. Thomas-Osip. 2006. Aqueous Alteration Affecting the Irregular Outer Planets Satellites: Evidence from Spectral Reflectance. Icarus 180, 453-463.

*      F. Vilas, P.S. Cobian, N.G. Barlow, and S.M. Lederer. 2005. How much material do the radar-bright craters at the Mercurian poles contain? Planetary and Space Science 53, Vol 14-15, 1496-1500.

*      Lederer S.M., D.L. Domingue, F. Vilas, M. Abe, T.L. Farnham, K.S. Jarvis, S.C. Lowry, Y. Ohba, P.R. Weissman, L.M. French, H. Fukai, S. Hasegawa, M. Ishiguro, S.M Larson, and Y. Takagi, 2005. Physical characteristics of Muses-C target 1998 SF36 (25143).  Icarus 173, 153-165.

*      F. Vilas, K.S. Jarvis, E.S. Barker, S.M. Lederer, M.S. Kelley, and T.C. Owen. 2004. Iapetus dark and bright material: Giving compositional interpretation some latitude. Icarus 170, 125-130.

*      Lederer S.M. and F. Vilas. 2003. Spectrophotometry of Kuiper Belt Objects 20000 Varuna, 2000 EB173 and Centaur 10199 Chariklo. Earth, Moon and Planets 92, Issue 1, 193-199.

*      Lederer S.M. and H. Campins. 2002. Evidence for chemical heterogeneity in the nucleus of C/1995 01 (Hale-Bopp). Earth, Moon and Planets 90, Issue 1, 381-389.

*      Lederer S.M., H. Campins, D.J. Osip, and D.G. Schleicher. 1999. Gaseous Jets in Comet Hale-Bopp (1995 O1).  Earth, Moon and Planets 78, Issue 1-3, 131-136.

*      Schleicher D.G., R.L. Millis, D.J. Osip, and S.M. Lederer. 1998. Activity and the Rotation Period of Comet Hyakutake (1996 B2). Icarus 131, 233-244.

*      Schleicher D.G., S.M. Lederer, R.L. Millis, and T.L. Farnham. 1997. Photometric Behavior of Comet Hale-Bopp (C/1995 O1) Before Perihelion.  Science 275, 1913-1915.

*      Gustafson, B.A.S. and S.M. Lederer. 1996. Interstellar Grain Flow through the Solar Wind Cavity around 1992.  Physics, Chemistry and Dynamics of Interplanetary Dust. ASP Conference Series 104, 35-38.

*      Lederer S.M., M.S. Marley, B. Mosser, J.P. Maillard, N.J. Chanover, and R.F. Beebe. 1995.  Albedo Inhomogeneities and Jovian Seismology.  Icarus 114, 269-277.