Letters of Intent received in 2017

LoI 2019-1990
Solar System Astrometry, Dynamics, and Ephemerides

Date: 25 June 2019 to 29 June 2019
Location: Pasadena, CA, United States
Contact: William Folkner (william.m.folkner@jpl.nasa.gov)
Coordinating division: Division A Fundamental Astronomy
Co-Chairs of SOC: J.-E. Arlot (Observatoire de Paris)
Steven Chesley (JPL)
Elena Pitjeva (Inst of Applied Astronomy RAS)
Paolo Tanga (Observatoire de la Côte d'Azur)
Chair of LOC: Shantanu Naidu (JPL)



Ephemerides for Sun, planets, natural satellites, asteroids, Kuiper-belt objects; Gravity fields, rotation models, coordinate systems, and interior structure of planets and satellites; Tidal interactions;New observations from planetary spacecraft, planetary radar, space-borne astrometry, pulsar timing.



The last decades have shown continuous evolution in measurements and estimated ephemerides of the bodies of the solar system. In the most recent decade, measurements to spacecraft orbiting planets and flying by dwarf planets have required updates to physical models needed to fit the ephemerides to the accuracy of the measurements. These models include sensitivity to the orientation of the planets and satellites and their tidal interactions that in turn are related to the interior structure of the bodies. Increased ground- and space-based astrometry and planetary radar have greatly improved the accuracy of ephemerides for natural satellites, asteroids, and Kuiper-belt objects. Orbits of near-Earth asteroids are of particular interest for assessing potential for impact events. The structure of the Kuiper belt and extreme Kuiper-belt object have been widely discussed as possible being organized by planet-sized bodies not yet discovered.

This Symposium will focus on the most recent and accurate measurements and models affecting the orbital and rotational dynamics of the solar system bodies. The measurements will span from ground and space-based astrometry, planetary radar, measurements of spacecraft in orbit about or flying by planets and small bodies, and pulsar timing. Dynamical model development will include newly significant relativistic terms, including the Lense-Thirring effect; rotational models and related interior structure models; tidal interactions of planets and their satellites; non-gravitational effects including the Yarkovsky effect; and challenges in long-term predictions including chaotic effects. Current accuracies in fitting ephemerides will be presented; and challenges in measurements and modeling for long-term modeling and future improvements in solar system ephemerides.