The Mass of Asteroid 10 Hygiea
Abstract
We estimate the mass of the fourth largest asteroid, 10 Hygiea, to be 9.02± 0.26 × 10^{19} kg (GM = 6.02 ± 0.17 km^{3}/s^{2} or 0.454± 0.013 × 10^{10}; GM_{⊙}). While the leastsquares estimate is consistent with values published elsewhere [1], the precision of our result is an order of magnitude finer than other results based on a single perturbed asteroid. This estimate relies wholly upon a close approach to asteroid 3946 Shor that took place 1998 Mar 29.90726 TDB at a distance of 0.014399 AU and relative velocity 0.914 km/s. Because of the substantial effect of that encounter, the mass estimate is insensitive to mass variations in other large Shor perturbers. The precision of the result was afforded by a series of high precision astrometric observations of Hygiea and Shor obtained at Table Mountain Observatory from 1996 through 2004. The IRASderived diameter of 407 ± 7 km [2] leads to a bulk density estimate of 2.55± 0.15 g/cm^{3}.
[1] G. Michalak (2001) A&A 374, 703711.
[2] E. Tedesco et al. (2002) AJ 123, 10561085.
 Publication:

AAS/Division of Dynamical Astronomy Meeting #36
 Pub Date:
 May 2005
 Bibcode:
 2005DDA....36.0505C