Circular No. 6727
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/cfa/ps/cbat.html
Phone 617-495-7244/7440/7444 (for emergency use only)


GRB 970828
     F. E. Marshall, Goddard Space Flight Center (GSFC); and J. K.
Cannizzo and R. H. D. Corbet, GSFC and Universities Space Research
Association, on behalf of the RXTE Science Operations Team, report
the detection with the RXTE PCA of an x-ray source whose position
appears consistent with that reported on IAUC 6726: "Multiple slews
across this position, beginning at Aug. 28.890 UT and lasting a
total of 40 min, revealed a source intensity in the band 2-10 keV
of about 0.5 mCrab.  Since we know of no catalogued x-ray sources
at this position, we believe this is the detection of an x-ray
afterglow from this burst.  A refined error box should be possible
after more detailed analysis."


SUNGRAZING COMETS
     C. St. Cyr, Naval Research Laboratory, on behalf of the SOHO-
LASCO Consortium (cf. IAUC 6685), reports the discoveries by Doug
Biesecker and Bernard McCarty (University of Birmingham) of four
more apparent Kreutz-sungrazing comets in archival SOHO-LASCO C3
coronagraph data.  Measurements by St. Cyr and Biesecker have been
reduced by G. V. Williams and are given on the MPECs cited below.
No tails were seen in the images of C/1996 O2 (MPEC 1997-Q04) and
C/1996 O3 (MPEC 1997-Q05), whose peak apparent magnitudes were
about 8.  Tails were evident for comets C/1996 O1 (MPEC 1997-Q03)
and C/1996 O4 (MPEC 1997-Q06), whose peak magnitudes were
estimated as about 7 and 6, respectively.  Approximate discovery
positions are as follows:

     1996 UT           R.A. (2000) Decl.         Comet
     July 21.419       7 50.1      +18 18      C/1996 O1
          23.195       7 51.4      +17 16      C/1996 O2
          25.120       8 02.1      +17 33      C/1996 O3
          27.031       8 06.0      +16 28      C/1996 O4


COMET 43P/WOLF-HARRINGTON
     Total CCD magnitude estimates:  Aug. 8.07 UT, 14.1 (A. Galad
and A. Pravda, Modra, Slovakia, 0.6-m reflector); 12.10, 14.1 (H.
Mikuz, Crni Vrh Observatory, Slovenia, 0.36-m reflector + V filter);
22.08, 13.3 (Galad and Pravda); 26.12, 14.3 (Galad and Pravda).

                      (C) Copyright 1997 CBAT
1997 August 29                 (6727)            Daniel W. E. Green