Xuan JiGraduate Student

Research Focus:
Exoplanets; Planetary Climate; Orbital Dynamics


BS in Astronomy, Beijing Normal University, 2020


Research Interests

My primary focus is on understanding how orbital dynamics influence planetary climates. My goal as a researcher is to uncover what types of planetary architectures that favors habitability. I believe analyzing individual planets in isolation cannot fully determine habitability, but examining entire planetary systems provides a more holistic perspective. The final architectures result from processes that are critical to habitability, such as planet formation, volatile delivery (late veneer) and loss, orbital evolution and the associated climate evolution. I am generally interested in how these process shape the habitability and I believe planetary architecture could be a better indicator for inferring habitability. 

My proposed PhD thesis is to investigate the effects of orbital eccentricity and its evolution on planetary climate, with focuses on defining the inner edge of the habitable zone and eccentricity-driven snowball bifurcation. I crafts low-order mathematical models, serving as a simplified framework to capture the essence of climate dynamics, and I also uses Global Climate Models (GCMs) for a more comprehensive investigation of complex climate feedback mechanisms. 

In addition to my thesis work, I am working on two side projects: studying how outgassed atmosphere of magma planets depends on their distance from their star, and investigating how sweeping secular resonances driven by eccentric gas giant contributes to the formation of water-rich planets. I've contributed to research on how volatile were distributed on Earth during its early accretion, and how rotational rate affects the formation of clouds. 



Ji, X., and D.S. Abbot (in prep): Variable Eccentricity-Driven Snowball Bifurcation and Hysteresis of Planetary Climate, in prep

Ji, X., N. Bailey, D. Fabrycky, E.S. Kite, J.H. Jiang and D.S. Abbot, 2023: Inner Habitable Zone Boundary for Eccentric Exoplanets. The Astrophysical Journal Letters, 943(1), p.L1.

Williams, D.A. X. Ji, P. Corlies and J.M. Lora, 2024: The Effects of Rotation Rate on Clouds on Terrestrial Planets. The Astrophysical Journal, 963, 36,

Gu, J.T., B. Peng, X. Ji, J. Zhang, H. Yang, S. Hoyos, MM. Hirschmann, E.S. Kite, and R.A.Fischer 2024: Earth’s Earliest Atmosphere and Volatile Loss During Accretion. Earth and Planetary Science Letters, 629, 118618

Jiang, J. H., X. Ji, N. Cowan, R. Hu, and Z. Zhu, 2019: Empirical predictions for the period distribution of planets to be discovered by the Transiting Exoplanet Survey Satellite. The Astronomical Journal,158 (2), 96

Jiang, J. H., R. Burn, X. Ji, K. A. Fahy, and P. Eggenberger, 2022: Angular momentum distributions for observed and modeled exoplanetary systems. The Astrophysical Journal,924 (2), 118,

Jiang, J. H., D. Zhao, X. Ji, B. Xie, and K. A. Fahy, 2021: Revisiting the planet mass and stellar metallicity relation for low-mass exoplanets orbiting GKM class stars. Universe,7 (4)

Cao, S., M. Biesiada, J. Qi, Y. Pan, X. Zheng, T. Xu, X. Ji, and Z.-H. Zhu, 2018: Cosmological investigation of multi-frequency VLBI observations of ultra-compact structure in z∼3 radio quasars. European Physical Journal C,78 (9), 749

Liu, T., S. Cao, J. Zhang, S. Geng, Y. Liu, X. Ji, and Z.-H. Zhu, 2019: Implications from Simulated Strong Gravitational Lensing Systems. The Astrophysical Journal,886 (2), 94