Hostname: page-component-7bb8b95d7b-l4ctd Total loading time: 0 Render date: 2024-09-11T17:37:16.659Z Has data issue: false hasContentIssue false
  • English
  • Français

The Asteroid Mass Determination Project at The U.S. Naval Observatory

Published online by Cambridge University Press:  12 April 2016

James L. Hilton  and
Ronald C. Stone
James L. Hilton
Affiliation:
U.S. Naval Observatory, 3450 Massachusetts Ave. NW, Washington, DC 20392, USA
Ronald C. Stone
Affiliation:
U.S. Naval Observatory Flagstaff Station, P.O. Box 1149, Flagstaff, AZ 86002, USA

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Asteroid masses are the largest source of unmodeled forces in current planetary ephemerides research. Williams (1984) showed that the asteroids produce km size perturbations in the position of Mars. However, the masses of only three asteroids are known to better than 10%, and only six other asteroid masses have been determined at all.

Detecting the mass of an asteroid is difficult because the observed quantity is the change in the mean motion of a second, perturbed asteroid. Asteroid masses are small, so the change in the mean motion is typically on the order of 0."015 yr−1. Thus, excellent orbit determinations are needed both before and after the perturbing encounter. This requires high precision observations over as many oppositions as possible.

Hilton (1997) determined the mass of 15 Eunomia to within 25% by detecting perturbations of 1313 Berna. The greatest source of uncertainty in determining the mass of Eunomia was the very poor coverage and accuracy of pre-encounter observations. Hilton (1998) has determined the masses of 1 Ceres, 2 Pallas and 4 Vesta, all based on mutual interactions. The uncertainties in the masses are 1% for Ceres, 3% for Pallas, and 7% for Vesta. The masses of Ceres and Pallas are the best so far, and the mass for Vesta corroborates previous determinations of its mass.

Type
Extended Abstracts
Information
International Astronomical Union Colloquium , Volume 172: Impact of Modern Dynamics in Astronomy , 1999 , pp. 361 - 362
Copyright
Copyright © Kluwer 1999

References

Helmer, L., and Morrison, L.V.: 1985, ’Carlsberg Automatic Meridian Circle’, Vista Astr., 28, 505 CrossRefGoogle Scholar
Hilton, J.L.: 1997, ‘The Mass of 15 Eunomia from Observations of 1313 Berna and 1284 Latvia’, Astron. J., 114, 402 CrossRefGoogle Scholar
Hilton, J.L.: 1998, ’U.S. Naval Observatory Ephemerides of the Largest Asteroids’, submitted to Astron. J.CrossRefGoogle Scholar
Hilton, J.L., Seidelmann, P.K., andMiddour, J.; 1996, ‘Prospects for Determining Asteroid Masses’, Astron. J., 11, 2319 CrossRefGoogle Scholar
Stone, R.C.: 1997, ’CCD Astrometry of Asteroids as Determined in the Extragalactic Reference Frame’, Astron. J., 113, 2317 CrossRefGoogle Scholar
Urban, S.E., Corbin, T., and Wycoff, G.: 1998, ’The ACT Reference Catalog’, Bull. Am. Astr. Soc, 29, 1306 Google Scholar
Williams, J.G.: 1984, ‘Determining Asteroid Masses from Perturbations on Mars’, Icarus, 57, 1 CrossRefGoogle Scholar