Department of Physical Science, Physics              Home Address: 
  New Mexico Highlands University                        P.O. Box 3732
  Las Vegas, New Mexico 87701                            Las Vegas, NM 87701
  Ph. # (505) 454-3148                                   Ph.# (505) 425-0768

  e-mail: eryan@psi.edu or                              Tucson Office Address:
          eryan@cs.nmhu.edu                              Planetary Science Institute
  WWW: http://www.psi.edu/EVR/evrgen.html or            620 North Sixth Avenue 
  WWW: http://helios.nmhu.edu/eryan/evrgen2.html         Tucson, AZ 85705, Ph.# (520) 622-6300

Ph.D., University of Arizona, Planetary Geophysics, (minor: Planetary Physics), 1992
M.S., Astronomy (physics minor), New Mexico State University, 1985
B.A., Physics, Rutgers University, NCAS, 1982

WORK EXPERIENCE

August 1998 - Present - Visiting Professor of Physics, New Mexico Highlands University.

December 1992 - Present - Research Scientist, Planetary Science Institute.

September 1985 - November 1992 - Research Associate, Planetary Science Institute

February - September 1997 - Program Director, Discovery Park's Gov Aker Observatory . Responsibilities included overseeing the day to day operations of the Observatory facility, assisting in the design, organization, and implementation of programming features and educational projects (including student research projects), and offsetting operations costs through acquisition of externally funded grants for the Observatory .

August - December 1996 - Visiting Professor , New Mexico Highlands University. Responsibilities included teaching and developing new curriculum materials for an Introductory Astronomy course, and an Earth Science laboratory, refinement of a Geology Major , and directorship of education outreach programs to local schools. An internet mini-course in Environmental Science and Remote Sensing was also outlined and designed.

April - August 1996: Research Scientist , National Optical Astronomy Observatories (NOAO). Duties included education outreach to middle schools and development of internet curriculum modules in math and science as part of the Project Galileo Education Outreach program (website designed: http://www.jpl.nasa.gov/galileo/sepo/). Organization for publication of a book documenting the cruise portion of the Galileo Spacecraft Mission was also accomplished.

Research Summary ( Planetary Science Institute) :

• Theoretical studies of collisions and the fragmentation process using a two- dimensional continuum damage numerical hydrocode, modified to include strength effects and the Grady-Kipp fragmentation algorithm. Code predictions were validated at small size-scales by reproducing fragment size distributions from both laboratory impact experiments on catastrophic disruption (see below), and explosive disruption experiments of finite targets under applied external pressures. The hydrocode is then used to determine how collisional outcome depends on target size, providing a better understanding of impact processes in the solar system (e.g., asteroid collisional evolution, planetary accretion, ring system dynamics, etc.).

• The design and implementation of an experiment program to study impacts and their collisional outcomes under various initial conditions. The goal is to obtain some predictive capability for fragment size and mass-velocity distributions, energy partitioning between target and projectile, and the collisional energy required for catastrophic fragmentation. Over 100 impact experiments were conducted at the Ames Vertical Gun Range (Moffett Field, CA).

• Played a major role (PI, Co-I) in writing proposals and securing funding for the theoretical and experimental programs described above.

• Image processing and analysis as part of the Galileo Mission Project. Using the VICAR image processing package, a mosaic of Australia was created from Galileo spacecraft images. Also used the IRAF package to study the cratered surface of asteroids Gaspra, Ida, and Dactyl from spacecraft images. Craters were measured using a semi-automated method.

• Lead Scientist developing education programs involving scientist/educator teams and the use of Internet resources. Created and maintains the World Wide Web (WWW) site for PSI (http://www.psi.edu), through which some of this material is disseminated. Has also helped to organize and develop the Galileo SSI Team website which provides education materials to the general public, utilizing images returned from the mission. Further, is part of a team responsible for producing educational CD-ROM's for the Cassini and TOPEX/Poseidon NASA missions.

• Science mentor to undergraduate students from the NASA Spacegrant Program, and a similar outreach program for high school students. Also served as Education Exhibit Coordinator for the AAS's 28th Division for Planetary Science's Meeting , Tucson, October 1996.

• Comet studies: data reduction of infrared photometry of Comet Halley and an analysis of the silicate emission feature.

• Have refereed papers for Icarus, the Journal of Geophysical Research, and Planetary and Space Science; and reviewed proposals for NASA's Planetary Geology and Geophysics program.
• Member of the organizing committee for the 5^th International Workshop on Catastrophic Disruption of Small Bodies in the Solar System, July 1998.

August 1985 Master's Thesis:

"Interstellar Extinction and the Assumption of Heterogeneous Dust Grains"

Description: The interstellar extinction curve is theoretically modeled assuming heterogeneous particles. Effective medium (for the determination of grain optical properties) and Mie scattering theories are used.

1983-1985 - TA/Research Assistant, Dept. of Astronomy, NMSU

Description: Teaching assistant for astronomy and planetary astronomy courses. Also performed photometric data collection and reduction of Delta Scuti variable stars. Additional research involved the study of Jupiter's cloud morphology using Pioneer and Voyager imaging data. Cloud features were tracked to provide wind vector profiles which are used to determine momentum transport in Jupiter's atmosphere. (Paper given on this topic at the 1983 DPS meeting)

1982-1983 - Teaching Assistant, Department of Physics, NMSU

Description: Laboratory instructor and grader for introductory level physics course

COMPUTER SKILLS

Extensive experience with FORTRAN-77, exposure to C, and familiar with IBM PC-compatibles, MacIntosh computers, SUN-OS (UNIX), and VAX (VMS) computers. Also experienced with WordPerfect, MS WORD, TeX, LaTeX, AXUM, EXCEL, LOTUS, MONGO, SIGMAPLOT, IRAF, and VICAR software packages, as well as hypertext markup language (HTML).

PROFESSIONAL MEMBERSHIPS/ SERVICE

American Geophysical Union
American Astronomical Society, Division of Planetary Sciences
American Institute of Physics
NASA Planetary Astronomy Program Panel Member; MUSES-C Science Team selection, 1999

AWARDS

March 1982: Elected to Phi Beta Kappa

Summer 1981: Awarded participation in the Summer Institute on Planets and Climate (Goddard Inst. Space Studies/Columbia Univ.)

MEDIA RELATIONS

December 1996: Television appearance on Sightings "Threat from Space" segment regarding the hazards involved in asteroid impacts on the Earth.

PUBLICATIONS

Ryan, E.V., D.R. Davis, and I. Giblin (1999). A Laboratory Impact Study of Simulated Edgeworth-Kuiper Belt Objects.
Submitted to Icarus.

Ryan, E.V. (1999). Asteroid Fragmentation and Evolution of Asteroids. Ann. Rev. of Earth and Planetary Sciences, in preparation.

Hartmann, W.K., P. Farinella, D. Vokrouhlicky, S.J. Weidenschilling, A. Morbidelli, F. Marzari, D. Davis, and E.V. Ryan (1999). Reviewing the Yarkovsky Effect: New Light on the Delivery of Stones and Irons from the Asteroid Belt. Meteoritics & Planetary Science, in press.

Ryan, E.V., and D.R. Davis (1999). The Impact Disruption of Cooled Iron Meteorites. To be submitted to Icarus.

Ryan, E.V. and D.R. Davis (1999). Ejecta Mass-Velocity Distribution from Catastrophic Disruption Experiments. To be submitted to Icarus.

Ryan, E.V., and H.J. Melosh (1998). Impact Fragmentation: From the Laboratory to Asteroids. Icarus 133, 1-24.

Melosh, H.J., and E.V. Ryan (1997). Asteroids: Shattered but not Dispersed. Icarus, 129, 562.

Chapman, C.R., E.V. Ryan, W.J. Merline, G. Neukum, R. Wagner, P.C. Thomas, J. Veverka, and R.A. Sullivan (1996). Cratering on Ida. Icarus 120, 77-86.

Davis, D.R., E.V. Ryan, and P. Farinella (1994). Asteroid Collisional Evolution: Results from Current Scaling Algorithms. Planet. Space Sci. 42, 599-610.

Martelli, G., E.V. Ryan, A.M. Nakamura, and I. Giblin (1994). Catastrophic Disruption Experiments: Recent Results. Planet. Space Sci. 42, 1013-1026.

Benz, W., E. Asphaug, and E.V. Ryan (1994). Numerical Simulations of Catastrophic Disruption: Recent Results. Planet. Space Sci. 42, 1053-1066.

Ryan, E.V. (1992). Catastrophic Collisions: Laboratory Impact Experiments, Hydrocode Simulations, and the Scaling Problem. Ph.D. thesis, University of Arizona: Tucson.

Melosh, H.J., E.V. Ryan, and E. Asphaug (1992). Dynamic Fragmentation in Impacts: Hydrocode Simulation of Laboratory Impacts. Journal of Geophysical Research 97, 14735-14759.

Ryan, E.V., W.K. Hartmann, and D.R. Davis (1991). Impact Experiments 3: Catastrophic Fragmentation of Aggregate Targets and the Relation to Asteroids. Icarus 94, 283-298.

Ryan, E.V., and H. Campins (1991). Comet Halley: Spatial and Temporal Variability of the Silicate Emission Feature. Astronomical Journal 101, 695-705.

Davis, D.R. and E.V. Ryan (1990). On Collisional Disruption: Experimental Results and Scaling Laws. Icarus 83, 156-182.

Fujiwara, A., P. Cerroni, D. Davis, E. Ryan, M. Di Martino, K. Holsapple, and K. Housen (1989). Experiments and Scaling Laws for Catastrophic Collisions. In Asteroids II (R. Binzel, M. Matthews, and T. Gehrels, eds. Univ. of Arizona Press), 240-265.

Campins, H.C. and E.V. Ryan (1989). The Identification of Crystalline Olivine in Cometary Silicates. Astrophys. J. 341, 1059-1066.

ABSTRACTS

Ryan, E.V., D.R. Davis, and Ian Giblin (1998). Experimental Studies of the Fragmentation of Simulated Edgeworth-Kuiper Belt Objects. LPSC XXIX .

William K. Hartmann, Paolo Farinella, Stu Weidenschilling, Eileen Ryan, David Vokrouhlicky, Francesco Marzari, Dominique Spaute, Donald R. Davis (1997). Yarkovsky Effects: Possible Consequences on Meteorites and Asteroids. LPSC XXVIII .

William K. Hartmann and Eileen V. Ryan (1996). Possible Evidence of Yarkovsky Depletion of Debris from the Asteroid Belt and Effects on Asteroid Surfaces. 28th DPS, Tucson, BAAS .

E.V. Ryan and C.R. Chapman (1996). Spectral Variations on Ida: A Space Weathering Trend? Meteoritics, 59th Meteoritical Society Meeting .

E.V. Ryan (1996). Cratering Impacts into Finite Targets: Comparing Experiments, Code Simulations, and Scaling Laws. LPSC XXVII , 1117-1118.

E.V. Ryan and H.J. Melosh (1995). Asteroids: Shattered but not Dispersed. AGU, Suppl. , Vol. 76, p. 336.

The Cratering Record on Ida (1995). C.R. Chapman, E.V. Ryan, and W.J. Merline. 27th DPS, Hawaii, BAAS .

On How to Scale Disruptive Collisions (1995). D.R. Davis and E.V. Ryan. LPSC XXVI, 319-320.

Asteroid Collisions: The Impact Disruption of Cooled Iron Meteorites (1994). E.V. Ryan and D.R. Davis. 26th DPS, Washington, D.C., BAAS 26, 1180.

Energy Partitioning in Catastrophic Collisions (1994). E.V. Ryan. and D.R. Davis. LPSC XXV, 1175-1176.

Hydrocode Simulations and Scaling (1993). E.V. Ryan. The 4th International Workshop on the Catastrophic Disruption of Small Solar System Bodies, Gubbio, Italy.

Laboratory Impact Experiments (1993). E.V. Ryan. The 4th International Workshop on the Catastrophic Disruption of Small Solar System Bodies, Gubbio, Italy.

Asteroid Collisional Studies: Results Using Scaling Laws from Hydrocode Models and Dimensional Analysis. (1993). D.R. Davis, E.V. Ryan, and P. Farinella. IAU Symposium No. 160, ACM, Belgirate, Italy.

Ejecting Basaltic Achondrites from Vesta: Hydrodynamical Impact Modes (1993). E. Asphaug, H.J. Melosh, and E.V. Ryan. LPSC XXIV, , 45-46.

Asteroid Collisions: Target Size Effects and Resultant Velocity Distributions (1993). E.V. Ryan. LPSC XXIV, 1227-1228.

Asteroid Collisional Evolution: Results Using New Scaling Algorithms (1993). D.R. Davis, E.V. Ryan, and P. Farinella. 25th DPS-Boulder, BAAS, Vol. 25, No. 3, 1116-1117.

Understanding Asteroid Collisions: The Effect of Target Size on Collisional Outcome (1992). E.V. Ryan and H.J. Melosh. 24th DPS-Munich, BAAS, Vol. 24, No. 3, 961.

Theoretical Predictions for Fragment Size Distributions (1992). E. Asphaug, H.J. Melosh, and E.V. Ryan. LPSC XXIII, 45-46.

Hydrocode Simulation of Explosive Disruption: External Pressure and Gravity (1992). E.V. Ryan, E. Asphaug, and H.J. Melosh. LPSC XXIII, 1193-1194.

A Numerical Laboratory for Fragmentation Studies: Some Insights Into Collisional Processes and Outcomes (1991). E. Asphaug, H.J. Melosh, and E.V. Ryan. LPSC XXII, 37-38.

Laboratory Impact Experiments: Ejecta Velocity Distributions (1991). E.V. Ryan and D.R. Davis. LPSC XXII, 1153-1154.

Hydrocode Predictions of Collisional Outcomes: Effects of Target Size (1991). E.V. Ryan, E. Asphaug, and H.J. Melosh. LPSC XXII, 1155-1156.

Impact Processes in the Solar System: New Understandings Through Numerical Modeling (1991). E. Asphaug, H.J. Melosh, and E.V. Ryan. LPSC XXII, press release.

Rubble Piles Galore: Initial Results from Hydrocode Calculations of Catastrophic Disruption (1991). E. Asphaug, D.R. Davis, and E.V. Ryan. Asteroids, Comets, Meteors 1991, Flagstaff, Arizona.

Regolith Ejection from Asteroids (1990). E. Asphaug, E.V. Ryan, and H.J. Melosh. IAU Dust Colloquium #126, Kyoto, Japan, 129.

Continuum Modeling of Catastrophic Collisions. E.V. Ryan, E. Asphaug, and H.J. Melosh (1990). IAU Dust Colloquium #126, Kyoto, Japan, 130.

Two-Dimensional Fragmentation Hydrocode (1990). E. Asphaug, E.V. Ryan, and H.J. Melosh. LPSC XXI, 28-29.

Impact Experiments: Catastrophic Fragmentation of Aggregate Targets (1990). E.V. Ryan, D.R. Davis, and W.K. Hartmann. LPSC XXI, 1055-1056.

Collisional Disruption Experiments: Impact Strength Analysis and Velocity Distributions (1989). E.V. Ryan and D.R. Davis. LPSC XX, 932-933.

Identification of Crystalline Silicates in Cometary Dust (1988). H. Campins and E.V. Ryan. 172nd Meeting of the AAS, Kansas City, Missouri, Bulletin of the AAS.

Application of New Scaling Laws of Collisional Outcomes (1987). D.R. Davis and E.V. Ryan. 19th DPS-Pasadena, Bulletin of the American Astronomical Society, Vol. 19, No. 3, 892.

The Structure of the Silicate Emission in Comet Halley (1987). H. Campins and E.V. Ryan. 19th DPS-Pasadena, Bulletin of the American Astronomical Society, Vol. 19, No. 3, 868.

Laboratory Experiments on Catastrophic Disruption (1987). E.V. Ryan and D.R. Davis. Second International Workshop on Catastrophic Disruption of Small Solar System Bodies, Belgrade, Yugoslavia.