[IAUC] IAUC 9069: S/2009 (93) 1, S/2009 (93) 2; C/2009 Q4 [25139-2009/08-R1]

[IAUC mailing list]

                                                  Circular No. 9069
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS en CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT en CFA.HARVARD.EDU (science)
URL http://www.cfa.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)


S/2009 (93) 1 AND S/2009 (93) 2
     F. Marchis and B. Macomber, Carl Sagan Center at the SETI
Institute and University of California at Berkeley; J. Berthier and
F. Vachier, Institut de Mecanique Celeste et de Calcul des
Ephemerides, Observatoire de Paris; and J. P. Emery, University of
Tennessee, Knoxville, report that adaptive-optics images were
recorded of (93) Minerva, a large C-type main-belt asteroid, with
the 10-m Keck II telescope [+ NIRC2 camera (angular resolution up
to 0".042, corresponding to a spatial resolution of 65 km) + Fe II
filter (central wavelength at 1.64 microns)] between Aug. 16.57 and
16.64 UT, with the target at r = 2.117 AU and phase angle 20.0 deg.
The direct images reveal that the large minor planet has an almost-
spherical shape with an average diameter of 145 km.  Additionally,
these observations show the presence of a companion about 4 km in
diameter at 0".41 (projected distance of 630 km) in p.a. 275 deg
detected in every image recorded over the 1.8-hr baseline.  Careful
analysis of three images indicates the presence of a second
satellite (about 3 km) and located closer to the primary at an
apparent distance of 380 km (0".25) in p.a. 209 deg.  With (87)
Sylvia (cf. IAUC 8582), (45) Eugenia (cf. IAUC 8817), and (216)
Kleopatra (cf. IAUC 8980), this is the fourth multiple system with
two small-kilometer-sized satellites to be discovered and imaged in
the main asteroid belt.


COMET C/2009 Q4 (BOATTINI)
     A. Boattini reports his discovery of a strongly condensed
comet with coma diameter about 8" (slightly elongated in p.a. 250
deg) in CCD images taken with the Catalina 0.68-m Schmidt telescope
(discovery observation tabulated below); Catalina images taken by
R. E. Hill on Aug. 28.4 UT show a small nuclear condensation with a
2" coma and a narrow tail about 10"-15" in p.a. 290 deg.  Following
posting on the `NEOCP' webpage, R. Ligustri (Udine, Italy) writes
that his CCD images on Aug. 29.4 (remotely using a 0.25-m reflector
near Mayhill, NM) show a slightly diffuse coma with diameter about
15".  J. V. Scotti notes that images taken on Aug. 30.5 with the
Spacewatch 1.8-m reflector show a 9" coma and a 0'.68 tail in p.a.
257 deg.

     2009 UT             R.A. (2000) Decl.       Mag.   Observer
     Aug. 26.47241    4 27 20.05   + 8 18 42.1   18.9   Boattini

The available astrometry, preliminary parabolic orbital elements [T
= 2009 Nov. 1.603 TT, q = 1.50024 AU, i = 11.627, Peri. = 301.086,
Node = 135.512 (equinox 2000.0)], and an ephemeris appear on MPEC
2009-Q84.

                      (C) Copyright 2009 CBAT
2009 August 31                 (9069)            Daniel W. E. Green