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IAUC 5909: OJ 287; 1993e

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                                                  Circular No. 5909
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM     EASYLINK 62794505

OJ 287
     M. Kidger, Instituto de Astrofisica de Canarias; L. Takalo,
Tuorla Observatory; and the 'OJ94 team' report:  "Recent monitoring
of OJ 287 shows it to have reached its brightest level since 1984.
CCD observations by Kidger with the LAC-80 telescope (Teide Observatory,
Tenerife) give the following V magnitudes:  Nov. 27.131 UT,
15.11; Dec. 6.090, 14.68; 6.139, 14.37; 6.176, 14.50; 7.279, 15.13.
J. Mattei (AAVSO) and D. Wills (University of Texas) report the
following visual magnitude estimates:  Dec. 7.284, [15.3 (D. York,
Abiquiu, NM); 8.225, [14.9 (York); 9.241, 14.6 (York); 9.25, 14.80
(P. Boltwood, Ontario, CCD + V filter); 10.246, 15.0 (York); 14.031,
15.1 (G. Poyner, Birmingham, England); 14.263, 15.4 (York); 15.254,
15.3 (York); 14.660, [15.4 (S. Sakuma, Kanagawa-ken, Japan).  A
major outburst of this object was predicted for 1994 July/August by
Sillanpaa et al. (1988, Ap.J. 325, 628) on the basis that the
outbursts are caused by the 11.6-yr orbital period of a binary black
hole.  A more recent examination of the lightcurve (Kidger et al.
1992, A.Ap. 264, 32) suggests that the true period is rather shorter
and gave a revised prediction for the maximum of the outburst in
early 1994 March.  The recent data suggest that the rise to maximum
may now have initiated, or that this may be a small precursor outburst
similiar to the one observed before the main outburst in 1983.
Lightcurve monitoring is urgently requested at all wavelengths to
establish whether or not this is the predicted outburst and to
permit the observed lightcurve behavior to be contrasted with models
of the predicted propagation at different frequency ranges."

     D. K. Yeomans and P. W. Chodas, Jet Propulsion Laboratory,
report that they closely confirm the computations by B. G. Marsden on
IAUC 5906.  They note that the Jupiter impact times in July 1994
are still uncertain by a few hours, but that the new times show
that the impact points (defined to be the points where the cometary
fragments reach the 1-bar level in Jupiter's atmosphere), though
still on Jupiter's dark side, are significantly closer to the morning
terminator than has previously been indicated.  The jovigraphic
latitudes at impact range from -47o to -49o, and the earth-Jupiter-
comet angles at impact range from 95o to 100o.

1993 December 17               (5909)            Daniel W. E. Green

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