Celestial Mechanics and Dynamical Astronomy

, Volume 100, Issue 1, pp 27–42

Astrometric masses of 21 asteroids, and an integrated asteroid ephemeris

Open Access
Original Article

DOI: 10.1007/s10569-007-9103-8

Cite this article as:
Baer, J. & Chesley, S.R. Celestial Mech Dyn Astr (2008) 100: 27. doi:10.1007/s10569-007-9103-8


We apply the technique of astrometric mass determination to measure the masses of 21 main-belt asteroids; the masses of 9 Metis (1.03 ± 0.24 × 10-11 M), 17 Thetis (6.17 ± 0.64 × 10-13 M), 19 Fortuna (5.41 ± 0.76 × 10-12 M), and 189 Phthia (1.87 ± 0.64 × 10-14 M) appear to be new. The resulting bulk porosities of 11 Parthenope (12±4%) and 16 Psyche (46±16%) are smaller than previously-reported values. Empirical expressions modeling bulk density as a function of mean radius are presented for the C and S taxonomic classes. To accurately model the forces on these asteroids during the mass determination process, we created an integrated ephemeris of the 300 large asteroids used in preparing the DE-405 planetary ephemeris; this new BC-405 integrated asteroid ephemeris also appears useful in other high-accuracy applications.


N-body Asteroid Ephemerides Asteroid masses Astrometric masses Asteroid porosity 
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Copyright information

© Springer Science+Business Media B.V. 2007

Authors and Affiliations

  1. 1.South UniversityPittsburghUSA
  2. 2.Jet Propulsion LaboratoryPasadenaUSA

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