
\documentstyle{crckapbk}

\begin{opening}
\title{PROSPECTS FOR DETERMINING MASSES FOR ASTEROIDS}
\author{JAMES L. HILTON P. KENNETH SEIDELMANN}
\institute{U.S. Naval Observatory\\3450 Massachusetts Ave., NW\\Washington, DC 20392\\USA}
\author{JAY MIDDOUR}
\institute{Code8103\\Naval Research Laboratory\\4555 Overlook Ave., SW\\Washington, DC 20375\\USA}
\date{}
\end{opening}

\begin{document}

\begin{abstract}
Integrations of the orbits of 4538 asteroid with mean distances from 1.52 AU to
5.20 AU were made.  The integrations started at 1 Jan. 1950 and ran through 1
Jan. 2030.  Comparison of these integrations produced several thousand
encounters of less than 0.05 AU for the larger asteroids (diameter greater than
200 km) and less than 0.01 AU for all asteroids.  This database was then
searched for encounters for which the deflection of one asteroid by another was
large enough to make a determination of the mass with an uncertainty of 50\% or
less.  A total of 460  such encounters were found between 1950 and 2015.  For
each individual encounter, the derived mass should have an uncertainty from
50\% to less than 1\%, depending on the amount deflection of the encounter and
provided sufficient high precision observations are available.  For the 254
encounters in the past, there are several opportunities, if the observations
exist, to make determinations of the asteroid masses.  For the 206 encounters
in the future, a coordinated observing campaign would greatly enhance the
knowledge of asteroid masses and densities.  There are 11 encounters between
smaller asteroids that should produce mass determinations.  In addition, there
are 17 asteroids that have encounters with more than one other asteroid and 16
instances of, at least temporary, resonances between pairs of asteroids.
\end{abstract}

\end{document}
