Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 5391: 1991o; 1991t

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 5390  SEARCH Read IAUC 5392
IAUC number


                                                  Circular No. 5391
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
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
MARSDEN or GREEN@CFA.BITNET    MARSDEN or GREEN@CFAPS2.SPAN


PERIODIC COMET CHERNYKH (1991o)
     Further observations of the splitting of the nucleus (cf. IAUC
5347) have been reported by S. M. Larson (Sept. 7, 9, Oct. 7, 8),
J. V. Scotti and T. Gehrels (Sept. 17, Oct. 2, 15, 16, Nov. 5), J.
Luu and D. Jewitt (Oct. 4-6), and R. H. McNaught (Oct. 5).
     Z. Sekanina, Jet Propulsion Laboratory, California Institute of
Technology, reports: "A solution based on 29 positional observations
of the two nuclei between Sept. 7 and Nov. 5 indicates that the
companion (the fainter nucleus) separated from the primary at 3.3 AU
from the sun, on 1991 Apr. 14.7 +/- 4.1 UT.  The separation velocity
is found to be higher than that for any other split comet: 15.00 +/-
0.93 m/s along the radius vector in the direction of the sun, 0.60
+/- 0.15 m/s in the direction perpendicular to the radius and toward
the direction from which the comet has come, and 0.23 +/- 0.03 m/s
in the direction of the comet's north orbital pole.  The secondary
has been subjected to a differential nongravitational deceleration
of 189 +/- 17 units of 10E-5 solar attraction and, in the terminology
introduced elsewhere for the split comets (Sekanina 1982, in Comets,
ed. L. L. Wilkening, Univ. Arizona, p. 251), it represents a
minor companion.  The solution satisfies the observations with a
mean residual of +/- 0".33.  The correlation between the deceleration
and the endurance that applies to most other split comets suggests
that the companion should disappear shortly.  The ephemeris
shows no major change in the configuration until around perihelion,
by which time the probability of the companion's survival is
virtually nil."


PERIODIC COMET HARTLEY 2 (1991t)
     Total visual magnitude estimates (cf. IAUC 5372):  Oct. 25.16
UT, 9.5 (H. Mikuz, Ljubljana, Yugoslavia, 0.20-m reflector); 28.19,
8.7 (J. Jahn, Bodenteich, Germany, 0.20-m reflector); Nov. 3.49, 9.2
(A. Hale, Las Cruces, NM, 0.41-m reflector); 6.25, 9.9 (A. Pereira,
Cabo da Roca, Portugal, 0.15-m reflector); 11.20, 10.1 (Mikuz);
12.52, 9.4 (C. S. Morris, Pine Mountain Club, CA, 0.26-m reflector);
16.55, 10.2 (R. Donner, Isla Vista, CA, 0.25-m reflector); 17.14,
10.6 (B. H. Granslo, Fjellhamar, Norway, 0.20-m reflector); 18.40,
10.1 (J. E. Bortle, Stormville, NY, 0.32-m reflector).


1991 November 21               (5391)             Daniel W. E. Green

Read IAUC 5390  SEARCH Read IAUC 5392


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


Valid HTML 4.01!