Central Bureau for Astronomical Telegrams
IAUC 3463: Sats OF SATURN
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Read IAUC 3464
Circular No. 3463
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
A. W. Harris, Jet Propulsion Laboratory, reports that observations
by J. Gibson and himself with the 2.5-m reflector at Mount
Wilson Observatory suggest that the satellite 1966 S 2 attained its
greatest elongations from Saturn around the following times: Mar.
13.16 UT (west), 13.51 (east), 14.54 (west), 15.2 (west) and 17.32
(west). Several other condensations, some of them obviously transient
ring knots, were also noted. Three of them, each ~ 1 mag fainter
than 1966 S 2, were somewhat more persistent and showed motion
suggesting that they might be satellites. The designations, inferred
times of greatest elongations and separations of these objects
from Saturn were: 1980 S 7, Mar. 13.29, 23" east; 1980 S 8, Mar.
15.19, 24" east; 1980 S 9, Mar. 15.27, 25" west (clear of rings).
J. Lecacheux, B. Fort, T. Fauconnier, M. Dreux and L. Vapillon,
Meudon Observatory; and P. Laques, A. Auge and R. Despiau, Pic du
Midi Observatory, communicate the following separations (uncertainty
+/- 0".2) of 1966 S 2 east (+) or west (-) of Saturn's center: Feb.
29.022 UT, -20".09; Mar. 1.0571, +21".76; 1.0575, +21".43; 1.0634,
+20".78; 16.9439, +22"; 17.9661, -22".20; 18.0401, -24".64; 18.0443,
-23".90; 18.0494, -23".33; 18.1052, -17".74; 18.1065, -17".57. The
observations were made using a Lallemand electronographic camera and
a CCD camera on the 1.05-m Pic du Midi reflector. The best exposure
(Mar. 18.0401) shows the starlike object very clearly detached
from the A ring, brighter than Saturn VII (Hyperion) but fainter
than Saturn I (Mimas); the inferred time of greatest western elongation
is Mar. 18.017 UT. The following ephemeris has been deduced
from these observations and those by Pascu and by Smith et al. on
IAUC 3454, 3456 and 3457: greatest eastern elongation = 1980 Mar.
18.316 UT + light time + 0.0019 (U - 45o.6) + 0.69468 E. [Editorial
Note. This formula is also in good agreement with the above
observations by Harris and Gibson. On the other hand, it indicates a
greatest eastern elongation on 1979 Dec. 9.3 UT, rather than Dec.
9.5 UT; cf. the observation by Mulholland on IAUC 3430.]
P. Lamy and N. Mauron, Laboratoire d'Astronomie Spatiale,
Marseilles, report that observations with the Chiran 1-m telescope at
the Haute Provence Observatory showed 1966 S 2 to be 24" west of
Saturn's center on Mar. 15.983 UT. A faint nebulosity (mag ~ 16),
possibly another satellite, was detected on several plates; this
object, designated 1980 S 10, attained a maximum elongation of 61".4
west of Saturn's center on Mar. 16.024 UT (cf. 1980 S 6, IAUC 3457).
1980 March 31 (3463) Brian G. Marsden
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