Searching for Duplicity Among Near-Earth Asteroids (original) (raw)
NASA/ADS
Abstract
Even before the discovery by Galileo of a small moon orbiting the minor planet 243 Ida, there was a growing body of evidence indicating that it is not unusual for asteroids to have companions or to be double. Radar ranging, photometric studies, and occultation observations have all suggested the presence of asteroid companions. If duplicity (or multiplicity) turns out to be common among near-Earth asteroids (NEAs), it would suggest that many asteroids in such orbits have undergone significant collisional evolution. To determine if this is indeed the case would require observing a much larger sample of NEAs than can be investigated by radar ranging, spacecraft encounters, or occultations. It appears that ground-based optical astrometry could contribute in a significant way to this investigation by providing highly accurate measurements of the motion of asteroids about the barycenter of double systems. Orbit residuals of asteroid observations made recently with the 0.2-meter transit telescope at Flagstaff, reduced with respect to the ACT, show an rms of about 50 mas. Preliminary computations by the authors indicate that this level of accuracy is sufficient to detect wobbles of the centers-of-light on the order of 50 km for objects within 1.5 AU of Earth. With the 1.3-meter telescope, now under construction at the Flagstaff Station, a substantially better accuracy should be achievable, given the ability to make numerous observations on a single night and to compute an asteroid's apparent position differentially as it passes through a given field of view. In this paper, we will discuss the parameter space of asteroid-companion pairings that are presently detectable and the larger set which should be available to the new telescope.
Publication:
AAS/Division of Dynamical Astronomy Meeting
Pub Date:
September 1998
Bibcode: