Lunar and Planetary Institute

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Dr. Julianne I. Moses
Professional Background


Ph.D., Planetary Science, June 1991
Minor: Geophysics
California Institute of Technology

A.B. (Honors), Physics, June 1985
Cornell University


  • Photochemical modeling – planetary and satellite atmospheres
  • Extrasolar planets – atmospheric composition, chemistry
  • Aerosols – properties, formation, behavior, scattering characteristics
  • Planetary surfaces – composition, atmosphere-surface interactions


  • Senior Research Scientist, Space Science Institute (Feb 2010 to present)
  • Visiting Scientist, Lunar and Planetary Institute (Feb. 2010 to present)
  • Staff Scientist, Lunar and Planetary Institute (April 1994 to Jan. 2010)
  • NRC Research Associate, NASA Ames (Feb. 1992 to March 1994)


Space Science Institute, Feb 2010 to present

  • Investigating how the atmospheric composition of Uranus and Neptune is expected to change as a function of latitude, altitude, and time due to seasonally variable photochemistry.  Comparing results with Spitzer/IRS and Gemini/TEXES data (with G. Orton and T. Greathouse).

  • Developing tropospheric photochemistry and aerosol-microphysics models (the latter with E. Barth) for Jupiter and Saturn to investigate the underlying processes that control the gas-phase composition, aerosol structure, vertical and meridional distribution of constituents, and their possible variations with season.  Comparing model results with Galileo NIMS and Cassini CIRS and VIMS data (with L. Fletcher and P. Irwin)

  • Constraining the flux of interplanetary dust grains to the atmospheres of the giant planets and Titan (with A. Poppe and G. Delory) and examining the consequences of this external material on atmospheric chemistry and composition

  • Investigating the chemical diversity of “hot Neptune” exoplanet atmospheres as a function of atmospheric temperature, metallicity, and bulk C/O ratio; applying the results to GJ 436b in an attempt to explain puzzling transit and eclipse observations (with M. Line and others).  Concluding that GJ 436b may have a very-high-metallicity atmosphere (~200-2000x solar).

  • Investigated the influence of the atmospheric C/O ratio on the chemistry and composition of the extrasolar giant planets; compared the results with eclipse observations of several exoplanets (with N. Madhusudhan, C. Visscher, R. Freedman).  Concluded that exoplanets like WASP-12b, XO-1b, and CoRoT-2b could be carbon rich; discussed ways in which a giant planet could develop a higher C/O ratio than its host star.

  • Reviewed the role of chemical kinetics in controlling the atmospheric composition of extrasolar giant planets.  Discussed observational consequences and examined the current evidence for disequilibrium kinetic processes on exoplanets.

  • Investigated the influence of disequilibrium chemistry on the atmospheric composition of the extrasolar giant planets HD 189733b and HD 209458b using a coupled thermochemical and photochemical kinetics and transport model; compared results to transit and eclipse observations of these planets (with J. Fortney, C. Griffith, C. Visscher, and others); determined that disequilibrium chemistry (both photochemistry and transport-induced quenching) are more important for the cooler exoplanets, whereas equilibrium should prevail throughout most of the photosphere for the hottest planets. Determined key CH4-CO quench mechanisms for brown dwarfs and giant planets (with C. Visscher).

  • Investigated hydrocarbon and oxygen photochemistry on Uranus to help interpret infrared emission spectra from the Spitzer Space Telescope (with G. Orton et al.); determined global-average stratospheric abundances for CH4, C2H2, C2H6, C3H4, C4H2, CO2, and upper limits for CH3; determined D/H ratio from CH3D; constrained eddy diffusion coefficients (which parameterize the strength of atmospheric mixing) in the stratosphere of Uranus; determined that the global-average abundances of C2H2 and CH4 – and by implication the effective stratospheric eddy-diffusion coefficients – do not seem to have changed in the ~20 years from the Voyager to Spitzer eras

  • Investigated seasonal photochemistry, stratospheric circulation, and the vertical and meridional distribution of hydrocarbon and oxygen species on the giant planets using both 1-D and 2-D photochemistry/transport models; compared results to various infrared ground-based and spacecraft observations. Aided the development of the first stratospheric GCM for Saturn (A. J. Friedson), the interpretation of Cassini data from Saturn (S. Guerlet et al., J. Hurley et al., J. Sinclair et al., S. J. Kim et al.), and the interpretation of ground-based TEXES data from Neptune.

  • Investigated nitrogen chemistry in the deep and shallow troposphere of Jupiter; determined dominant quench mechanisms and quench levels for HCN, N2, CH3NH2; made predictions for abundances of as-yet-unidentified nitrogen-bearing species; determined why the HCN abundance is so low on Jupiter (with C. Visscher and others).

  • Developed the first-ever thermochemical and photochemical kinetics and transport model for giant planets (and other planets with thick atmospheres) to accurately track atmospheric composition from the thermochemical equilibrium regime in the deep atmosphere through the “quenched equilibrium” regime in the low-to-mid troposphere to the photochemical regime in the higher-altitude “photosphere” (with C. Visscher). Tested the model through investigation of the quenching of CO and HCN on Jupiter; discussed implications with respect to formation


  • Editorial Board, Icarus (2009–2011)
  • Editor, Journal of Geophysical Research – Planets (2003–2007)
  • Committee Member, NASA Planetary Systems Science Management Operations Working Group (PSS-MOWG, 2007-2010)
  • Committee Chair, JGR-Planets Editor Search Committee (2010)
  • Director, LPI Summer Intern Program (2004–2010)
  • Board Member, Cassini Senior Review (2009)
  • Scientific Organizing and/or Program Committees, DPS meeting (2004), Lunar and Planetary Science Conference (1995-1997, 2003–2005, 2009–2010), Planetary Atmospheres Workshop (2007), Magnetospheres of the Outer Planets Workshop (2007)
  • Steering Committee, NASA Outer Planet Assessment Group (2005–2007)
  • Committee Member, Giant Planets Panel, NAS/NRC Solar System
  • Exploration Survey “Decadal Study” (2001–2002)
  • Nominating Subcommittee, Division for Planetary Sciences of the American Astronomical Society (2001–2003)
  • Discipline Leader, International Jupiter Watch: Laboratory and Theory Discipline (1998-2003)
  • PDS Atmospheres Node Advisory Group (1996–present)
  • Advisor, LPI Summer Intern Program (1995, 1998, 2000, 2003, 2005, 2007–2009, 2012)
  • Panel Chief, NASA Outer Planets Research Program Review Panel
  • Panel Chief, NASA Mission Instrument Review Panel
  • Panel Member, proposal review panels for NASA Planetary Atmospheres Program, NASA Cassini Data Analysis Program, NASA Planetary Astronomy Program, NSF Astronomy and Astrophysics Program, NASA Mission Review Panels, NASA Instrument Review Panels, NASA Interdisciplinary Exploration Science Program, Hubble Space Telescope Selection Program, NASA Jupiter Data Analysis Program Review Panel (typically 1-2 panels per year)
  • Research advisor for undergraduate students Katherine Rawlins, Stephen F. Bass, Veronica L. LaMothe, Amanda G. Sharp, Renee D. Naphas, Justin Troyer, Ayesha Mahmud, Aubrey D. Sperier, Sarah Saslow, Molly D. Richardson and postdocs Thomas K. Greathouse and Channon Visscher.
  • NASA Planetary Geology Undergraduate Research Fellowship (1984)
  • A.B. awarded with honors (Cornell, 1985)
  • Hartmann Prize in Experimental Physics (Cornell, 1985)
  • Phi Beta Kappa (Cornell, 1985)
  • Earle C. Anthony Graduate Fellowship (Caltech, 1985–1986)
  • NASA Graduate Student Research Fellowship (Caltech, 1987–1990)
  • Top Reviewer Award, Icarus (1992–1993)

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Last updated
May 30, 2013