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IAUC 6864: CM Dra; GRB 980329

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                                                 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."


GRB 980329
     S. Klose, H. Meusinger, and H. Lehmann, Thueringer
Landessternwarte Tautenburg, report:  "I-band images obtained on
Mar. 29.8-30.0 UT, using the Tautenburg Schmidt telescope (+
Schmidt-focus CCD camera), show an object with magnitude I about 20
at the position of the fading radio source reported by Taylor et
al. (http://gcn.gsfc.nasa.gov/gcn/gcn3/040.gcn3; R.A. = 7h02m38s.0,
Decl. = +38o50'44", +/- 1", equinox 2000.0).  This object was no
longer visible on I-band images taken on Mar. 31.8-31.9 with the
Tautenburg telescope (I > 21); it was also not found on an I-band
image taken on Apr. 1.85 with the Calar Alto 2.2-m telescope (+
CAFOS; I > 21).  No R-band counterpart of this object is seen on
Tautenburg images taken on Mar. 29.8-30.0 (R > 22).  Images are
available via http://www.tls-tautenburg.de/research/grb.html."

                      (C) Copyright 1998 CBAT
1998 April 6                   (6864)            Daniel W. E. Green

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