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Planetary and lunar ephemeris EPM2021 and its significance for Solar system research

Elena Pitjeva, Dmitry Pavlov, Dan Aksim, Margarita Kan

Proceedings of the International Astronomical Union, Volume 15, Symposium S364, 220–225 (2022)

DOI: 10.1017/s1743921321001447

Keywords: celestial mechanics, astrometry, ephemerides, solar wind, minor planets, asteroids, Moon

About the paper


We present an updated public version of EPM (Ephemerides of Planets and the Moon). Since the last public version, EPM2017, many improvements were made in both the observational database and the mathematical model. Latest lunar laser ranging observations have been added, as well as radio ranges of Juno spacecraft and more recent ranges of Odyssey and Mars Reconnaissance Orbiter. EPM2021 uses a new improved way to calculate radio signal delays in solar plasma and has a major update in the method of determination of asteroid masses. Also, a delay-capable multistep numerical integrator was implemented for EPM in order to properly account for tide delay in the equations of the motion of the Moon. The improved processing accuracy has allowed to refine existing estimates of the mass of the Sun and its change rate, parameters of the Earth–Moon system, masses of the Main asteroid belt and the Kuiper belt; and also to raise important questions about existing numerical models of solar wind.