A new approach to determining asteroid masses from planetary range measurements

We describe a new approach to estimate asteroid masses from planetary range measurements. The approach significantly simplifies the process of parameter estimation and allows an effective control of systematic errors introduced by the omission of asteroids from the dynamical model. All asteroid masses are adjusted individually thus avoiding the usual distinction between masses considered individually and masses based on densities within the C, S and M taxonomic classes. Regularization is achieved by accounting, on each mass, for a prior uncertainty determined from available estimations of asteroid diameters and densities. The new approach is used to fit the asteroid model of the JPL planetary ephemeris to Mars range data. The adjusted planetary solutions exhibit similar extrapolation capacity as previous releases of the JPL ephemeris. Up to 27 asteroid masses are determined to better than 35%. The masses agree well with estimates obtained independently by other authors. The determined masses are also robust with respect to cross-validation on a dataset with a shorter time-span and with respect to a different selection of asteroids in the model. (C) 2012 Elsevier Inc. All rights reserved.