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                                                  Circular No. 4159
Central Bureau for Astronomical Telegrams
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

     C. Hansen and B. Smith, on behalf of the Voyager Imaging
Science Team, report the discovery of a new satellite of Uranus.
The object, provisionally designated 1985 U1, is ~ 75 km in
diameter and at a distance of 86 000 km from the center of Uranus.

     D. Bonneau and R. Foy, CERGA, report that speckle interferometric
observations on the 3.6-m Canada-France-Hawaii Telescope
during 1984 May 27-29 lead to the following first direct measurements
of the uniform disk diameters of the principal satellites of
Uranus and Neptune: Uranus I (Ariel), angular diameter 0"103 +/-
0"003, corresponding to 1325 + 46 km; Uranus II (Umbriel), 0"079 +/-
0"003, 1025 +/- 33 km; Uranus III (Titania), 0"120 +/- 0"004, 1561 +/-
46 km; Uranus IV (Oberon), 0"120 +/- 0"004, 1561 +/- 46 km; Neptune I
(Triton), 0"098 +/- 0"003, 2074 +/- 64 km.

     S. M. Larson, Lunar and Planetary Laboratory, reports that
CCD images obtained by D. Levy and himself with the 1.5-m reflector
at the Catalina station on Jan. 6.1 UT show the result of a
major outburst.  A complex of curved sunward jets and a bright,
linear, antisolar 38" jet appears to be the same type of event
seen several times in the 1910 photographs.  The comet has been
showing episodes of activity in roughly two-day cycles, and on
Jan. 5.1 only remnants of the Jan. 4.1 jets were seen.  Since such
events may lead to a better determination of the nuclear rotation
period, observers are urged to watch for recurrences of the phenomenon
at multiples of the 2.17-day period reported by Sekanina on
IAUC 4151 (note also the communication by Itoh with Suisei
observations on IAUC 4155).  Spectra over the range 380-950 nm taken
with the same instrument showed no unusual emissions.

     J. Crovisier, Observatoire de Meudon, telexes that high-
resolution Fourier-transform infrared spectra were recorded on
1985 Dec. 19-23 at the Canada-France-Hawaii Telescope by J.-P.
Maillard, T. Encrenaz, M. Combes and himself.  Spectra in the 4.7
micron region at 0.005 mm**-1 resolution show no CO emission; a preliminary
upper limit of 10**28 s**-1 can be derived for the CO production
rate.  Other spectra with about 100 mm**-1 resolution were obtained
over 0.9-2.5 microns; the (0-0) band at 1.10 microns and the (1-0) band at
0.92 microns of the CN red system are clearly visible.

1986 January 9                 (4159)              Brian G. Marsden

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