Zdenek Sekanina and Paul W. Chodas
Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109
and
Milos Tichy , Jana Ticha, and Michal Kocer
Klet Observatory, Zatkovo nabrezi 4, CZ-370 01 Ceske Budejovice, Czech Republic
Received 2003 April 14; accepted 2003 May 20; published 2003 June 2;

Abstract.

Distant comets C/2002 A1 and C/2002 A2 make up a peculiar pair that moves about the Sun in virtually identical, somewhat unstable orbits, extending currently between about 4.7 and 29 AU from the Sun. The two objects, observed since late 2001, are unquestionably of common origin. Analysis of their relative motion indicates that their parent body split nontidally most probably between mid-1977 and early 1979 at a heliocentric distance of 22.5 +/- 0.1 AU and about 2.5 AU below the ecliptic, with a separation velocity of 2.7 +/- 0.2 m/s.
The motion of C/2002 A2, the secondary component that trails behind the primary, is found to be affected by a nongravitational deceleration of (13.4 +/- 1.5) x 10^(-5) units of solar gravitational acceleration relative to C/2002 A1, which is in a range of decelerations that companions of split comets are usually subjected to. C/2002 A2 was somewhat less condensed and, interestingly, brighter than C/2002 A1.

Subject headings: comets: general—comets: individual (C/2002 A1, C/2002 A2)—methods: data analysis

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