Central Bureau for Astronomical Telegrams
IAUC 4115: 1982i
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Circular No. 4115
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-495-7244/7440/7444
PERIODIC COMET HALLEY (1982i)
W. Landgraf, Max-Planck-Institut fur Aeronomie, Lindau, reports
that his investigation of the nongravitational forces in different
parts of the orbit indicates that the normal component A3 =
+0.01 +/- 0.01 near perihelion and A3 = -0.14 +/- 0.04 and +0.10 +/-
0.03 at r = 1.5 AU before and after perihelion, respectively,
suggesting that the comet's rotational axis is directed toward
orbital longitude (measured from perihelion in the sense of motion)
352.4 +/- 3.3 deg, orbital latitude +5.5 +/- 1.4 deg. The true uncertainties
are perhaps five times greater than the above formal mean errors.
M. Prieto, M. Kidger and J. Beckman, La Palma, report that
observations made during Sept. 26.11-26.25 UT with the IPCS (
resolution 2.0-nm, spectral range 370-720 nm) on the 2.5-m Isaac
Newton Telescope, using a 5" slit centered on the nucleus of P/Halley,
show strong CN emission out to a radius of 3'9 (the maximum length
possible for the slit); two bands of C2 and C3 can also be traced
out to this distance. Seven spectra were obtained at various position
angles, centered on the nucleus. From the fading of the lines
at large distances from the nucleus a coma diameter of as large as
9'-10' was estimated. Provisional analysis cannot yet confirm or
deny the suggested presence of an anti-tail.
P. D. Feldman and M. C. Festou report the first U.S.-European
IUE observations of P/Halley on Sept. 12 and 21. OH (0,0) band
emission and continuum are detected on both days. In addition,
the OH (1,0) and (1,1) bands are seen on Sept. 21. The OH (0,0)
band brightness is 150 R in a 10" x 15" aperture on Sept. 12.1 and
340 R on Sept. 21.9. The derived OH production rate (vectorial
model) is 2.0 x 10**28 s**-1 for Sept. 12.1 and 4.1 x 10**28 s**-1 for
Sept 21.9; L-alpha (~ 700 R in a 10" x 15" aperture) was detected on
Sept. 21.
Total visual magnitude estimates: Sept. 13.34 UT, 12.8 (J.
Bortle, Stormville, NY, 0.50-cm reflector); 15.02, 12.4 (J.-C.
Merlin, Le Creusot, France, 0.40-m reflector; 17.05, 13.1 (M.
Zanotta, near Como, Italy, 0.30-m reflector); 19.80, 15.0 (R.
Mosser, Valff, Alsace, France, 0.50-m reflector); 21.50, 12.2 (C.
S. Morris, near Mount Wilson, CA, 0.25-m reflector); 23.42, 12.1
(Morris); 25.38, 11.5 (R. King, Duluth, MN, 0.28-m reflector);
26.3, 12.0 (S. O'Meara, Cambridge, MA, 0.23-m refractor; tail 20"
in p.a. 314, jets 15" in p.a. 40, 10" in p.a. 130).
1985 October 2 (4115) Brian G. Marsden
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