Central Bureau for Astronomical Telegrams
IAUC 6192: Sats OF SATURN; V1333 Aql
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Circular No. 6192
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
A. S. Bosh, Lowell Observatory; and A. S. Rivkin, Lowell
Observatory and Lunar and Planetary Laboratory, report: "We have
discovered four probable satellites of Saturn, from twenty-seven
400-s images taken in the 890-nm methane band with the HST Wide
Field Planetary Camera 2 during an 11-hr span at the May 22 ring-
plane crossing. For each satellite, we give below the orbital
radius; the angular distance from Saturn at May 22.48584 UT
(negative values indicating that the satellite is west of Saturn);
the longitude at the same epoch (measured from the sub-earth
point); the approximate V magnitude at opposition; and the number
of images in which the satellite was detected: S/1995 S 1, 137450
+/- 200 km, -16".4, +120 deg, 17.2, 15; S/1995 S 2, 139700 +/-
300 km, -18".0, +69 deg, 16.3, 12; S/1995 S 3, 141050 +/- 100 km,
-10".5, +33 deg, 17.5, 14; S/1995 S 4, 146450 +/- 450 km, +14".2,
-44 deg, 18.3, 11. S/1995 S 1, S 2, and S 3 were identified in
each frame in which they were not close to Saturn or a bright
satellite. S/1995 S 4 was not identified in seven frames in which
it should have been visible, all before ring-plane crossing, when
the background noise was higher. Satellite positions were fitted
to a circular orbit in the plane of the rings, including terms
arising from Saturn's nonspherical gravity field. Maximum
residuals were in all cases < 0".5, and for S/1995 S 2 and S 3 were
no greater than 0".15, which is approximately the centering error.
All known satellites are accounted for except Saturn XVIII (Pan),
XV (Atlas), and XVI (Prometheus), which may be visible but are
still uncertain; the possibility exists that S/1995 S 1 is Atlas
and that S/1995 S 2 is Prometheus, although they would be 26 and 21
deg from their respective predicted positions. We see no
satellites outside the rings (the distance of which from Saturn at
the times of observation was > 20") with opposition V mag equal to
or brighter than 19, i.e., that of Saturn XIV (Calypso)."
V1333 AQUILAE
S. A. Ilovaisky and C. Chevalier, Observatoire de Haute-
Provence (OHP), communicate: "CCD photometry of V1333 Aql, the
optical counterpart of the recurrent x-ray transient Aquila X-1,
has been obtained at Haute-Provence with the 1.2-m telescope at
regular intervals since Mar. 11. The object was in quiescence (V =
19.2) until July 17, when it started brightening. Quick-look
magnitudes on July 25.0 UT yield V = 17.5, typical for these
recurring activity cycles. Monitoring will continue at OHP.
Observations are urged at radio and x-ray wavelengths."
1995 July 26 (6192) Daniel W. E. Green
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