Figure 1:Discovery images of the newly found Neptune satellite S/2003 N1 showing its motion relative to background stars and galaxies. Click on the image to learn more.
The new Neptune satellite S/2003 N1 (now named Psamathe) was announced on September 3, 2003 by the International Astronomical Union. Read the circular announcement below. The new Neptune satellite is about 38 kilometers in diameter and has an orbital period of about 26 years. It is the furthest known satellite of any planet.
See a table of Neptune's known satellites .
Circular No. 8193 Central Bureau for Astronomical Telegrams INTERNATIONAL ASTRONOMICAL UNION Mailstop 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 0081-0304 Phone 617-495-7440/7244/7444 (for emergency use only) SATELLITES OF NEPTUNE On Sept. 1, S. S. Sheppard, University of Hawaii, reported to the Minor Planet Center the discovery by D. C. Jewitt, J. Kleyna, and himself of a possible new satellite (mag R = 26) of Neptune with the 8.2-m Subaru reflector at Mauna Kea on Aug. 29.3 and 30.3 UT. He also reported observations from the same nights of S/2002 N 1 (IAUC 8047, MPEC 2003-A75). Later that day, in response to a request by B. G. Marsden (Minor Planet Center), M. Holman, Harvard- Smithsonian Center for Astrophysics, reported observations by J. Kavelaars and himself with the 4-m Blanco reflector at Cerro Tololo on Aug. 21.1 UT of S/2002 N 1, as well as observations on Aug. 19.0 of another Neptunian-satellite candidate that Holman felt might conceivably be identical with a satellite candidate observed in the same manner on 2001 Aug. 11.1. Computations by Marsden showed the new Sheppard and Holman objects to be same and that identity with the 2001 object was a distinct possibility. Holman was then able to locate this object, now designated S/2003 N 1, on two nights in each of July 2003 and Aug. 2002 (with T. Grav and W. Fraser as participating observers). The complete set of observations and a linked orbit by Marsden (a = 0.33 AU, e = 0.27, i = 124 deg, H = 10.8) are given on MPEC 2003-R19. The 2003 observations (including also some from June 3 and July 29 with the 6.5-m Clay reflector at Las Campanas) of S/2002 N 1 are given on MPEC 2003-R18, together with Marsden's improved orbit (a = 0.11 AU, e = 0.26, i = 112 deg, H = 9.8). (C) Copyright 2003 CBAT 2003 September 3 (8193) Daniel W. E. Green
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