Yuk L. Yung

Yuk L. Yung is Professor of Planetary Science at the California Institute of Technology and Jet Propulsion Laboratory Senior Research Scientist. He received his B.S. from the University of California in 1969 and his Ph.D. from Harvard University in 1974. His academic career at Caltech spans from Visiting Associate (1976), through Assistant Professor (1977-82), Associate Professor (1982-86), Professor (1986-2011, 2017-present), with an interlude as Smits Family Professor (2012-16). He also served as Jet Propulsion Laboratory Research Scientist (2014-15) before becoming Senior Research Scientist (2015-present).

Professor Yung's research focuses on planetary atmospheres across the solar system and beyond, with particular expertise in atmospheric chemistry, radiation processes, and the search for biosignatures. His work bridges theoretical modeling, laboratory experiments, and observational data, with applications to both planetary science and Earth's climate change issues. He has studied planets Mars, Venus, Jupiter, Uranus and Neptune, as well as moons including Io, Ganymede, Callisto, Titan and Triton, and exoplanets such as HD209458b.

His publication record spans decades with significant contributions including the first detection of water vapor in an exoplanet atmosphere (HD189733b). His research covers atmospheric chemistry of various gases including H₂, O₂, O₃, N₂, N₂O, H₂O, HDO, CO, CO₂, halogens, methane, higher hydrocarbons, ammonia, sulfur compounds and aerosols.

Professor Yung teaches Ge/Ay 159 (Astrobiology) and Ge/ESE 139 (Introduction to Atmospheric Radiation), courses that reflect his interdisciplinary approach to planetary science and atmospheric processes. His teaching covers topics from the emergence of life at hydrothermal vents to the search for biosignatures on exoplanets.

• Pioneering work on stratospheric chemistry that preceded Nobel Prize-winning research on chlorine effects
• First conclusive discovery of water vapor in exoplanet atmosphere (HD189733b)

Professor Yung's research demonstrates a consistent theme of synergy between modeling, laboratory experiments, and field observations, often in collaboration with colleagues at Caltech and JPL. His work has evolved from studies of solar system planets to the cutting-edge field of exoplanet characterization, while maintaining connections to Earth's atmospheric processes and climate change.