Central Bureau for Astronomical Telegrams
IAUC 3593: Sats OF SATURN; PKS 0735+178 AND 3C 371
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 3594
Circular No. 3593
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
SATELLITES OF SATURN
B. A. Smith, Lunar and Planetary Laboratory, reports that observations
by S. M. Larson and J. W. Fountain with the 1.5-m Catalina
reflector and new focal-plane coronagraph on Apr. 1.25 UT
showed 1980 S 6 ('Dione B') to lead Dione (Saturn IV) by 48o.1 +/- 0o.2,
in close agreement with the prediction on IAUC 3572. Further, an
unidentified satellite, designated 1981 S 1, with motion indistinguishable
from that of Enceladus (Saturn II), was recorded five
times during Apr. 1.27-1.32. Differential coordinates with respect
to the center of Saturn on Apr. 1.3003 UT were: Delta R.A. = +35".7 +/- 0".3,
Delta Decl. = +1".9 +/- 0".3. The object appears to be embedded in the E ring.
However, if it is actually located just outside the E ring, the satellite,
estimated at mv ~ 18, could be controlling the particle
distribution in the core of the E ring.
C. Veillet, CERGA, describing observations made on IIIa-J
plates at the direct Cassegrain focus of the 1.54-m Danish telescope
at the European Southern Observatory, notes that 31 observations
of 1980 S 6 during six nights Apr. 6-14 yield a mean separation
from Dione of 47o.89 +/- 0o.24 (p.e.). An unidentified satellite,
designated 1981 S 2, observed during six consecutive nights (Apr. 9-14)
has the following orbital elements: P = 1.8821 days, greatest
apparent eastern elongation = 1981 Apr. 11.1267 UT, 47".19 from the
center of Saturn. These elements fit the 41 available positions
within 0".35 (s.d.). 1981 S 2 may correspond to one or more of 1980
S 13, S 24 and S 25; its magnitude is at least 17. The above orbit
is very close to that of Tethys (Saturn III). If 1981 S 2 is supposed
to move in Tethys' orbit, its longitude difference from
Tethys is ~ 57o.9, close to the Saturn:Tethys L5 libration point.
PKS 0735+178 AND 3C 371
H. R. Miller, Georgia State University, writes that the BL Lac
object PKS 0735+178 and the N galaxy 3C 371 (which is related to
the BL Lac class of objects) are currently in a bright phase. The
following V magnitudes of PKS 0735+178 were obtained with the 1.3-m
telescope at Kitt Peak National Observatory: Mar. 29, 15.03; Mar.
30, 15.10; Mar. 31, 15.13; Apr. 1, 15.12. Corresponding V magni-
tudes of 3C 371 were: Mar. 31, 14.38; Apr. 1, 14.30. Both objects
have a history of optical variability, and spectrographic and radio
observations at this time would be particularly desirable.
1981 April 16 (3593) Brian G. Marsden
Read IAUC 3594
Our Web policy. Index to the CBAT/MPC/ICQ pages.
