Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 6669: SUNGRAZING COMETS; 96P

The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).

Read IAUC 6668 SEARCH Read IAUC 6670

View IAUC 6669 in .dvi or .ps format.
IAUC number 

                                                  Circular No. 6669
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)


SUNGRAZING COMETS
     G. E. Brueckner reports, for the SOHO-LASCO Consortium (which
consists of the Naval Research Laboratory, Laboratoire d'Astronomie
Spatiale, Max-Planck-Institut fur Aeronomie, and the University of
Birmingham), the discovery of four more comets (cf. IAUC 6650, 6653)
in images obtained by the LASCO white-light coronagraphs aboard the
ESA/NASA Solar and Heliospheric Observatory (SOHO) spacecraft.  The
following approximate discovery positions are summarized from the
more complete reductions by G. V. Williams on MPEC 1997-K10 to
1997-K13 from measurements by D. A. Biesecker and O. C. St. Cyr:

          UT           R.A. (2000) Decl.
     1996 Jan. 27.971      20 56.4      -20 01     C/1996 B3
     1996 Dec. 11.056      17 15.8      -27 03     C/1996 X1
               11.802      17 19.4      -27 11     C/1996 X2
     1997 Jan. 26.179      20 54.2      -20 33     C/1997 B2

C/1996 B3 was discovered only recently using automated search software
written by Biesecker.  The others were discovered in real time by
D. J. Lewis and Biesecker; S. T. Stezelberger; and Biesecker,
respectively.  The final analysis of the brightness of each object has
not been completed, but preliminary results (based on comparisons with
stars in the same coronagraphic field) by Biesecker and St. Cyr
suggest that C/1996 X2 had m1 = 7.5 and the others m1 > 8.0, with
variations evident for each object.  Orbital computations by the
undersigned on the same above-mentioned MPECs suggest that all these
SOHO comets are Kreutz sungrazers. with T = 1996 Jan. 28.71, Dec. 12.10,
Dec. 12.88 and 1997 Jan. 27.08 UT, respectively.  None of the four
comets was detected receding from the sun, in spite of continuing
observations in each case.


COMET 96P/MACHHOLZ 1
     This comet was detected (accidentally by Stezelberger) during
1996 Oct. 13.4-14.7 UT near the edge of the SOHO LASCO C3 coronagraphic
field.  St. Cyr estimated m1 = 4 or 5, much brighter than the sungrazing
comets reported above and on IAUC 6653.  The positions reduced by
Williams from St. Cyr's sun-related measurements and published on MPC
29710 are within 2' of this comet's expected position and confirm the
general correctness of the reduction procedure used for all of these comets.
     K. J. Meech, O. R. Hainaut and J. M. Bauer, University of Hawaii,
have reported observations of this comet with the 2.2-m reflector:
1997 Apr. 15.57 UT, m1 = 19.1; also observed on Apr. 17.6.

                      (C) Copyright 1997 CBAT
1997 May 23                    (6669)              Brian G. Marsden

Read IAUC 6668 SEARCH Read IAUC 6670

View IAUC 6669 in .dvi or .ps format.

Our Web policy. Index to the CBAT/MPC/ICQ pages.

Valid HTML 4.01!