Central Bureau for Astronomical Telegrams
IAUC 4142: 1982i
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 4143
Circular No. 4142
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)
I. de Pater, University of California, Berkeley; P. Palmer,
University of Chicago; and M. Schenewerk, University of Illinois,
report: "The 1667-MHz transition of OH was observed in P/Halley on
Nov. 13 and 16 with the Very Large Array in its D (the most
compact) configuration. The peak of the OH emission was displaced
from the comet's predicted position (from International Halley
Watch Astrometry Network orbital elements set 29) by Delta-R.A. = -3m54,
Delta-Decl. = -72". The observed flux was ~ 100 mJy. Most OH emission is
seen in clumps rather than in uniform distribution. Maps indicate
that the emission peaks strongly within the central 3', but also
clearly indicate structure on larger size scales. At the position
of the nucleus itself, there is no emission seen."
D. Despois, Observatoire de Bordeaux; T. Forveille, IRAM; J.
Schraml, Max-Planck-Institut fur Radioastronomie; and D. Bockelee-Morvan,
J. Crovisier, and E. Gerard, Observatoire de Meudon, telex:
"We have detected the HCN molecule in P/Halley with the IRAM 30-m
telescope. The (J = 1-0, F = 2-1) line at 88.6 GHz was observed
with the following equivalent brightness temperatures (TB): Nov.
20.0 UT, 0.300 +/- 0.045 K; 21.0 and 22.0, 0.070 +/- 0.015 K; and 23.0,
0.085 +/- 0.017 K. For all observations, the line width was ~ 1
km/s. On Nov. 23.0, the (F = 1-1) line was also detected, with TB
= 0.110 +/- 0.017 K, suggesting a non-LTE intensity ratio of the
hyperfine components. These observations suggest a daily variation
of the HCN production rate. Assuming a Bockelee-Morvan-et al.
(1984, A. Ap. 141, 411) excitation model, Q(HCN) was on the order
of 3 x 10**25 s**-1 on Nov. 21-23."
K. Jockers, Max-Planck-Institut fur Aeronomie, Lindau, communicates:
"An exposure of P/Halley obtained Nov. 12.882 UT at the 1-
m Hoher List Observatory telescope (with a focal reducer through an
interference filter), centered at the 2-0 comet tail band of CO+,
shows a disturbed plasma tail of a length exceeding 15', pointing
to the south and seen nearly head-on. An exposure on Nov. 15.887
shows an asymmetric coma with the denser part opposite to the
projected heliocentric velocity of the comet."
R. S. Patterson and T. G. Cave, Southwest Missouri State
University, write that 3.5-min-exposure photographs obtained with an
0.20-m Schmidt camera on Nov. 6.23 UT show a symmetrical and
uniform tail 13' long toward p.a. 286; 10-min exposures taken 48 hr
later indicated that the feature had disappeared entirely.
1985 November 26 (4142) Daniel W. E. Green
Read IAUC 4143
Our Web policy. Index to the CBAT/MPC/ICQ pages.
