IAUC 7980: S/2001 U 1; S/2002 (121) 1

The followingInternational Astronomical Union Circularmay be linked-to from your own Webpages, but mustnot otherwise be redistributed (seethese notes on the conditions underwhich circulars are made available on our WWW site).

---

ReadIAUC 7979 ReadIAUC 7981

ViewIAUC 7980 in.dvi or.ps format.

IAUC number

---

                                                  Circular No. 7980Central Bureau for Astronomical TelegramsINTERNATIONAL ASTRONOMICAL UNIONMailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)CBAT@CFA.HARVARD.EDU (science)URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304Phone 617-495-7440/7244/7444 (for emergency use only)S/2001 U 1     A new candidate for a satellite of Uranus, of mag R =25.3-25.5, was found by M. Holman, Harvard-Smithsonian Center forAstrophysics (CfA); J. Kavelaars, now at Dominion AstrophysicalObservatory; and D. Milisavljevic, McMaster University, with the4-m reflector at the Cerro Tololo Interamerican Observatory (CTIO)on 2001 Aug. 13.  Kavelaars obtained confirmatory images with theCanada-France-Hawaii Telescope on Aug. 25.  Following furthermeasurements by B. Gladman, from images obtained by P. Nicholsonand C. Dumas with the 5-m Hale reflector at Palomar on Sept. 21 andby J.-M. Petit with the European Southern Observatory 8.2-m UT3telescope at Paranal on Nov. 15, B. G. Marsden, CfA, provided aprediction for the 2002 opposition that allowed Gladman to recovera candidate for the object on Paranal images obtained by P.Rousselot and O. Mousis on 2002 Sept. 5, after which Holman, withthe help of T. Grav, confirmed the recovery on CTIO 4-m reflectorimages obtained on 2002 Aug. 13.   Marsden established definitivelyan orbit with a = 0.057 AU, e = 0.21, i = 166 deg (to the ecliptic)and that H = 12.8.  Full details of the astrometry and orbitcalculation, as well as a current ephemeris, are provided onMPEC2002-S64.S/2002 (121) 1     W. J. Merline, Southwest Research Institute (SwRI); P. M.Tamblyn, Binary Astronomy and SwRI; C. Dumas, Jet PropulsionLaboratory (JPL); L. M. Close, University of Arizona; C. R.Chapman, SwRI;  F. Menard, Observatoire de Grenoble; W. M. Owen,JPL; and D. C. Slater, SwRI; and J. Pepin, University of Colorado,report the discovery on Sept. 28.6 UT of a satellite of (121)Hermione (a C-type, Cybele-family asteroid of diameter 209 km) fromJ-, H-, and K'-band direct imaging with the 10-m Keck II Telescope(+ NIRC2/AO adaptive optics sysem) on Mauna Kea.  The satellite wastracked until it became inaccessible to the telescope; over this0.5-hr baseline, no relative motion was detected (a search forknown background/foreground small bodies with similar position andvelocity reveals no candidates closer than 1 deg that are ofsimilar brightness to the satellite).  On Sept. 28.6334, thesecondary was at 0".43 separation (projected separation 630 km) inp.a. 257 deg.  The K brightness difference is about 6 mag, givingan estimated diameter of the satellite of about 13 km.                      (C) Copyright 2002 CBAT2002 September 30              (7980)            Daniel W. E. Green

---

ReadIAUC 7979 ReadIAUC 7981

ViewIAUC 7980 in.dvi or.ps format.

---

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