Central Bureau for Astronomical Telegrams
IAUC 4148: 1982i
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Circular No. 4148
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)
D. Jewitt, K. Meech, and G. Ricker, Massachusetts Institute of
Technology, communicate: "Observations from McGraw-Hill Observatory
on Kitt Peak over 4 nights show variable structures in the inner
coma of P/Halley. Images were taken through broad and narrowband
interference filters using the MIT 'MASCOT' CCD camera on the 1.3-m
telescope. Jet-like structures were observed in position angles
358 and 313 on Nov. 29 UT. The jets extended 10 000 km in the
plane of the sky and had widths comparable to the atmospheric seeing.
The jets were visible in both broad and narrowband continuum
filters and are probably dust features. The jets showed no variation
in position angle or brightness in an observing interval of >
3 hr but were absent on the preceding and following nights."
Meech and Jewitt also report: "Observations of P/Halley with the
Kitt Peak 0.61-/0.91-m Schmidt telescope (with baked IIIa-J plates
and exposure times 30-60 min) show that extensive tail development
has occurred within the past month. Observations on Nov. 6-9
showed only a transient, faint anti-solar tail (length 20' on Nov.
6.20) which faded in < 1 day. Observations on Dec. 4-8 show a persistent
plasma tail (length > 2.5 deg) displaying a classical streamer
morphology. We are able to follow knots, kinks, and streamers in
the tail for up to 6 hr. The measured speeds of 3 tail knots are
190, 216, and 240"/hr (39, 45, and 50 +/- 5 km/s along the tail,
km/s), considerably less than the solar wind speed but similar to
the speeds measured in the tails of other comets. No evidence for
acceleration of the features is seen. Two episodes of ray formation
have been seen in 25 hr of observation; the rays form in ~ 1
hr and evolve over several hr, but fade in < 18 hr. The tail as a
whole shows gross brightness changes from night to night. No dust
tail is seen."
P. Lamy, Laboratoire d'Astronomie Spatiale, Marseille, and S.
Koutchmy, Institut d'Astrophysique, Paris, telex: "Four consecutive
1-hr-exposure IIIa-J hypered plates obtained between Dec. 6.79-6.96
UT by Koutchmy and J. C. Vial with the 0.62-m f/3 Schmidt telescope
of Haute Provence Observatory show a disturbed, narrow, plasma tail
of length > 2 deg. The tail's inner part deviates southward from the
anti-solar direction by 4.8 +/- 0.7 deg; the outer part widens and nears
the anti-solar direction. The point of bifurcation seems to move
radially outward with time."
1985 December 13 (4148) Daniel W. E. Green
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