Central Bureau for Astronomical Telegrams
IAUC 6407: Sats OF SATURN; 1996 JA1
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Circular No. 6407
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
Phone 617-495-7244/7440/7444 (for emergency use only)
SATELLITES OF SATURN
F. Roddier, Institute for Astronomy, University of Hawaii
(IfA); A. Brahic, Observatoire de Paris and Universite de Paris
(Paris); C. Dumas, IfA; C. Ferrari, Paris; J. E. Graves, M. J.
Northcott, and T. Owen, IfA; L. Perret, Paris; C. Roddier, IfA; and
P. Thebault, Paris, report: "A new adaptive-optics system developed
at the University of Hawaii was operated at the 3.6-m Canada-
France-Hawaii telescope during four nights spanning the 1995 Aug.
ring-plane crossing. Several hundred 15-, 30-, and 60-s exposures
were obtained in the bands I, J, H, and K; the average angular
resolution is 0".15 in the H band. Saturn X (Janus), XI
(Epimetheus), XII (Helene), XIII (Telesto), XIV (Calypso), XV
(Pandora), and XVI (Prometheus) were identified; positions are in
fair agreement with the new ephemerides deduced from Hubble Space
Telescope (HST) observations. Three additional objects --- S/1995
S 8, S/1995 S 9, and S/1995 S 10 --- have been discovered. The
number of fitted observations is given below, followed by our
estimate of the equivalent orbital radius and longitude for epoch
1995 Aug. 10.5 TDT (at Saturn), measured from the ascending node of
Saturn's equatorial plane on the earth's J2000.0 equator; the fits
include the effects of Saturnian J2 and J4 harmonics: S/1995 S 8,
16 observations, 141 400 +/- 1000 km, 323 +/- 1 deg; S/1995 S 9,
16, 141 400 +/- 2000 km, 315 +/- 1.8 deg; S/1995 S 10, 8, 140 050
+/- 100 km, 131.4 +/- 1.1 deg. S/1995 S 10 has been observed on
both Aug. 9 and 10; it is co-orbital to the F ring. This object is
most probably the candidate satellite S/1995 S 5, which was
observed by the HST on Aug. 10. S/1995 S 8 may be identified with
S/1995 S 7 observed by HST, since the observations are consistent.
The S/1995 S 9 azimuthal extent of 5 deg suggests an arc structure,
which may be embedded in the F ring; it cannot be linked with any
other objects discovered by HST at the same epoch."
1996 JA1
Further to IAUC 6402, M. Hicks reports that U. Fink was also
involved with the observations mentioned there. He adds that the
second-night data, which were obtained with the spectrograph slit
widened to 10" in order to eliminate tracking errors and
differential refraction, are in complete agreement with the first-
night data. The identification of 1996 JA1 as V type (eucrite) is
thus very secure.
(C) Copyright 1996 CBAT
1996 May 25 (6407) Daniel W. E. Green
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