Orbital Dynamics

Kepler's laws of planetary motion turn out to be far from the last word on planetary orbits. Orbits change over time, some changes are slow and periodic, others are chaotic and dramatic; these determine the architecture of planetary systems. In orbital dynamics research, we seek to discover the past and future of planetary systems - the diverse effects of gravity that shape where and how planets form and how their orbits evolve in time. We study the orbital evolution of planetary and satellite systems, and small bodies (asteroids and comets), as well as interplanetary dust, in the solar system and in exo-planetary systems. We seek discovery and understanding of the dynamical transport processes of planetary materials across vast distances in space and over geologically long times. We study how Earth's habitability is affected by its orbital history, and how orbital dynamics shapes extra-terrestrial environments.

Recent News

July 2020

• Kathryn Volk is now the Chair of the AAS Division on Dynamical Astronomy

• A new paper by Kathryn Volk (co-authored with Renu Malhotra) on the source of dynamical instability in multiplanet systems: "Dynamical instabilities in systems of multiple short-period planets are likely driven by secular chaos: a case study of Kepler-102" Volk & Malhotra 2020, AJ in press

• Steward Observatory Graduate Student Rachel Smullen and Kathryn Volk had a paper accepted about using machine learning to dynamically classify Kuiper belt objects: "Machine Learning Classification of Kuiper Belt Populations" Smullen & Volk, MNRAS in press

June 2020

• A new paper by Prof Renu Malhotra describes the discovery of low eccentricity bridges between first order mean motion resonances: On the Divergence of First Order Resonance Widths at Low Eccentricities
• Graduate Student Nathaniel Hendler led this new paper on measuring the sizes of 199 protoplanetary disks: The Evolution of Dust Disk Sizes from a Homogeneous Analysis of 1-10 Myr old Stars

March 2020

• Regents Professor Renu Malhotra co-authored this paper on Search for L5 Earth Trojans with DECam, Markwardt et al., MNRAS, 492(4):6105-6119 (2020)

February 2020

• Graduate student Hamish Hay successfully defended his PhD Dissertation, “A Tale of Tides: icy satellites, subsurface oceans, and tightly-packed planetary systems”
• Graduate student Teddy Kareta led this paper on the new interstellar object 2I/Borisov Carbon Chain Depletion of 2I/Borisov

December 2019 

• A new paper led by graduate student Teddy Kareta "Physical Characterization of the 2017 December Outburst of the Centaur 174P/Echeclus", (2019), Astronomical Journal, 158, 6.
• Regents Professor Renu Malhotra’s work featured in the Economist How the planets got their spots - The Economist, December 2019

November 2019

• Resonant Kuiper Belt Objects: a review, Geoscience Letters, 6:12 (2019). (a review paper by Regents Professor Renu Malhotra)

October 2019 

• Kathryn Volk’s work featured in UA News Beyond Jupiter, Researchers Discovered a 'Cradle of Comets'

August 2019

• A new paper by visiting graduate student Lan Lei and Regents Professor Renu Malhotra Neptune's resonances in the Scattered Disk, CMDA, 131, article ID 39, 26 pp. (2019)

April 2019

• A new paper led by graduate student Hamish Hay Tides Between the TRAPPIST-1 Planets

March 2019

• LPL’s 2019 Kuiper Award goes to graduate student Hamish Hay!

February 2019

• Nonlinear tidal dissipation in the subsurface oceans of Enceladus and other icy satellites (a new paper led by Hamish Hay)
• The case for a deep search for Earth's Trojan asteroids, Nature Astronomy (18 February 2019). (A Comment by Regents Professor Renu Malhotra)
• Regents Professor Renu Malhotra quoted in PBS Nova article Battle scars on Pluto and Charon, PBS Nova, February 2019

December 2018

• Regents Professor Renu Malhotra’s work featured in the New York Times A Journey into the Solar System’s outer reaches, New York Times, December 2018
• Regents Professor Renu Malhotra’s work featured in Science magazine Did the ancient Sun go on a diet? Science, December 2018

November 2018

• A paper led by Teddy Kareta "Rotationally Resolved Spectroscopic Characterization of Near-Earth Object (3200) Phaethon", (2018)

September 2018 

• A paper co-authored by graduate student Hamish Hay Ocean tidal heating in icy satellites with solid shells

June 2018 

• Associate Professor of Practice Steve Kortenkamp’s Project POEM featured in the UA News UA Encourages Visually Impaired Teens in STEM - June 13, 2018

December 2017

• Nathaniel Hendler led this paper on the transition disc of T Chameleon A likely planet-induced gap in the disc around T Cha