Circular No. 6875
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)
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CM DRACONIS
     H.-J. Deeg, Instituto de Astrofisica de Canarias; L. R. Doyle
and J. M. Jenkins, SETI Institute; and E. L. Martin, University of
California, Berkeley, write:  "The results of Guinan et al. on IAUC
6864 are inconsistent with our observational data.  From 32 of our
eclipse-minima timings obtained between May 1994 and Oct. 1996, we
obtained residuals from the expected O-C values measured to better
than 5.5 s; these O-C values were calculated from new epoch and
period values for the CM Dra system (Deeg et al. 1998, submitted to
A.Ap.).  We find no evidence of significant periodic variations in
the O-Cs, either at a period of 70.3 days or any other periods less
than a limiting value of about 3 yr (this maximum given by the
length of our observational coverage); the standard deviation of
our O-C values is 7.4 s, which makes any sinusoidal signal in the
eclipse-minima times with amplitudes of > 10.5 s extremely unlikely
(and amplitudes as high as 18 s certainly recognizable).  We also
report that the possible planetary transit eclipse of 0.08 mag
reported on IAUC 6425 was an artifact produced by a dust speck in
that night's CCD frames; there are no indications in our database
from 1994 to 1996 (617 hr) of any planetary transits with
amplitudes larger than 0.01 mag.  Our present phase coverage for
the detection of coplanar planets around CM Dra ranges from 92
percent for 10-day periods to 64 percent for 30-day periods.
From a work in progress (Doyle et al.), we can presently rule out
coplanar planets in this data set around CM Dra larger than 3.0
earth radii with orbital periods of less than about 30 days at a
confidence level of 90 percent."

                      (C) Copyright 1998 CBAT
1998 April 14                  (6875)            Daniel W. E. Green