Circular No. 6864 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A. IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions) BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science) URL http://cfa-www.harvard.edu/iau/cbat.html Phone 617-495-7244/7440/7444 (for emergency use only) CM DRACONIS E. Guinan, Villanova University; D. Bradstreet, Eastern College; I. Ribas, University of Barcelona; M. Wolf, Charles University; and G. McCook, Villanova University, report the detection of a probable brown dwarf or massive planet in the CM Dra (dM4.5+dM4.5) eclipsing-binary system: "Possible planetary transit eclipses (with depths of 0.08 mag) have been reported previously for CM Dra (see IAUC 6423, 6425). From extensive photometry obtained during Mar. 1996-Mar. 1998, seventeen eclipse timings were obtained. Least-squares solutions of the timing residuals show a sinusoidal variation in the arrival times of the eclipses, corresponding to an amplitude of 18 +/- 2 s and an orbital period of about 70.3 +/- 1.5 days. Adopting the systemic mass of CM Dra (M_1 + M_2 = 0.448 solar masses) and assuming a circular orbit, the size of the third body's orbit is about 0.27 AU. The mass of the third body is M_3 about 0.061 +/- 0.004 solar masses if its orbital plane is coplanar (or nearly so) with the eclipsing pair. The phasing of the light-time effect indicates that the object producing the effect is not the object that produced the planetary transit dimming events, so it is likely that CM Dra contains more than one substellar object. We are searching for possible transit eclipses from this body at the expected conjunction times; however, for a transit eclipse to occur, its orbital plane would have to be within 0.4 deg of exactly coplanar." (C) Copyright 1998 CBAT 1998 April 6 (6864) Daniel W. E. Green