Central Bureau for Astronomical Telegrams
IAUC 3577: PERIODIC 2060; 1980t; Sats OF SATURN
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Circular No. 3577
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 617-864-5758
PERIODIC COMET SCHWASSMANN-WACHMANN 1 AND (2060) CHIRON
J. Degewij, Jet Propulsion Laboratory; D. P. Cruikshank, University
of Hawaii; and W. K. Hartmann, Planetary Science Institute,
report: "The following V (10" diaphragm) and JHK (8" diaphragm) observations
of P/Schwassmann-Wachmann 1 have been made with the NASA
IRTF Telescope at Mauna Kea:
1980/81 UT V J-H H-K V-J
Dec. 8.6 17.55 +/- 0.10 +0.50 +/- 0.19 -0.16 +/- 0.25 +1.73 +/- 0.13
Feb. 5.6 13.52 +/- 0.10 +0.28 +/- 0.02 -0.07 +/- 0.02 +1.26 +/- 0.13
7.5 14.01 +/- 0.07 +0.33 +/- 0.02 +0.07 +/- 0.02 +0.93 +/- 0.07
The comet had an outburst in early February, and the colors are different
from those observed in other bright comets. We infer a possible
weak ice band during activity. The V-J color in December was
unusually red, suggesting a possible RD stony core. More observations
are warranted. Along with R. W. Capps, University of Hawaii,
we also observed (2060) Chiron during the same time period, the average
magnitude and colors being V = 18.6, J-H = +0.35 +/- 0.13, H-K =
+0.08 +/- 0.14. These colors rule out water ice as the dominant surface
material and strongly suggest a dark, stony surface material,
as found on many outer-solar-system bodies."
Further to the note on IAUC 3573, the bright coma had the appearance
of a spiral emanating from the nucleus of the comet. The
previous observation showing P/Schwassmann-Wachmann 1 in its quiescent
state was made on Feb. 1.
COMET BRADFIELD (1980t)
Total visual magnitude estimates: Jan. 24.98 UT, 7.2 (J.
Bortle, Stormville, NY, 10 X 50 binoculars; tail 0o.8 in p.a. 30o);
28.76, 9.5 (M. Verdenet, Bourbon-Lancy, France, 0.53-m reflector;
pear-shaped coma); 31.97, 7.4 (C. S. Morris, Harvard, MA, 20 x 80
binoculars); Feb. 2.04, 8.5 (P. Maley, Houston, TX, O.13-m refractor).
No further reports of the comet's possible duplicity have
been received (cf. IAUC 3569).
SATELLITES OF SATURN
Corrigendum. The new object reported on IAUC 3574 should have
been given the designation 1980 S 31, not 1980 S 29.
1981 February 23 (3577) Brian G. Marsden
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