Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 6515: Sats OF SATURN; C/1995 O1

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 6514  SEARCH Read IAUC 6516

View IAUC 6515 in .dvi or .ps format.
IAUC number


                                                  Circular No. 6515
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
     C. Roddier and F. Roddier, Institute for Astronomy (IfA), University
of Hawaii; A. Brahic, Observatoire de Paris; and J. E. Graves, M. J.
Northcott and T. Owen, IfA, report: "Images of Saturn's rings, taken in
Aug. 1995 with the University of Hawaii adaptive-optics system mounted on
the Canada-France-Hawaii telescope, have now been deconvolved and
carefully processed.  They show evidence for at least nine additional
objects all orbiting in the F ring.  A good orbital fit (including the
effects of the Saturnian J2 and J4 harmonics) was obtained for all of
them with a single distance of 140 500 +/- 500 km.  The following list
includes the three objects already announced on IAUC 6407.  As before,
the longitudes (uncertainty +/- 1 deg) are for the epoch 1995 Aug. 10.5
TT (at Saturn) and are measured from the ascending node of Saturn's
equator on the earth's J2000.0 equator: S/1995 S 11, longitude 302 deg,
estimated radius 12 km; S/1995 S 9, 317, 16; S/1995 S 12, 320, 10;
S/1995 S 7 = 1995 S 8, 325, 20; S/1995 S 13, 330, 12; S/1995 S 14, 46, 16;
S/1995 S 15, 105, 12; S/1995 S 16, 114, 10; S/1995 S 17, 116, 10;
S/1995 S 18, 118, 10; S/1995 S 19, 120, 10; S/1995 S 5 = 1995 S 10, 131, 20.
We also find some evidence for S/1995 S 11, S/1995 S 15, S/1995 S 16 and
S/1995 S 17 in the HST data (cf. IAUC 6243).  S/1995 S 12 is part of the
possible S/1995 S 9 arc structure mentioned on IAUC 6407, now resolved
into two components; we no longer see evidence for arc structures.  The 12
objects listed above cover a total longitude range of 135 deg.  Assuming
that objects are uniformly distributed, one can estimate that the F ring
contains some 32 of them with radii larger than 10 km."


COMET C/1995 O1 (HALE-BOPP)
     H. E. Matthews, National Research Council of Canada and Joint
Astronomy Centre; D. Jewitt, University of Hawaii; and W. M. Irvine,
University of Massachusetts, report the detection in C/1995 O1 of
HNC[4-3] at 362.6 GHz using the James Clerk Maxwell Telescope
on Dec. 1.0 UT.  Measured within a 13".5 (29 000 km)-diameter beam, the
integrated line intensity was 0.23 +/- 0.03 Ta* K km/s.  Using nearly
simultaneous observations of HCN[4-3], the HNC/HCN production ratio
is estimated as 0.07.  This is similar to the value measured earlier
in C/1996 B2 (IAUC 6353).  Since the two comets were observed at quite
different heliocentric distances (2.14 and 1.22 AU), the results
suggest that the observed HNC is a parent molecule present in the
nuclear ices and not a product of photochemistry in the coma.  The
HNC/HCN ratio is consistent also with an origin for these species in
an interstellar cloud (cf. Irvine et al. 1996, Nature 383, 418).

                      (C) Copyright 1996 CBAT
1996 December 6                (6515)              Brian G. Marsden

Read IAUC 6514  SEARCH Read IAUC 6516

View IAUC 6515 in .dvi or .ps format.


Our Web policy. Index to the CBAT/MPC/ICQ pages.


Valid HTML 4.01!