[meteorite-list] Solar system news

From: Matson, Robert <ROBERT.D.MATSON_at_meteoritecentral.com>
Date: Mon Oct 31 14:29:22 2005
Message-ID: <BE076B8CCE4CFE4D9598230D888B2ADF9385B1_at_0005-its-exs01.mail.saic.com>

Hi All,

Evidently jealous of all the attention that 2003 UB313 (affectionately,
unofficially known as "Xena") and its satellite (likewise, "Gabrielle")
have been getting, the largest KBO, Pluto, has upped the ante:

                                                  Circular No. 8625
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138,
U.S.A.
IAUSUBS_at_CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
CBAT_at_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)

S/2005 P 1 AND S/2005 P 2
     H. A. Weaver, Applied Physics Laboratory, Johns Hopkins
University; and S. A. Stern, Southwest Research Institute (SwRI) --
on behalf of a team including M. J. Mutchler (Space Telescope
Science Institute), A. J. Steffl (SwRI), M. W. Buie (Lowell
Observatory), and W. J. Merline, J. R. Spencer, E. F. Young, and
L. A. Young (SwRI) -- report the discovery of two new satellites of
Pluto. The objects, provisionally designated S/2005 P 1 and S/2005
P 2, were clearly detected (S/N > 35) in two different Hubble Space
Telescope ACS/WFC images on May 15.05 and 18.14 UT. On May 15,
S/2005 P 1 was 1".85 (1.85 arcsec) from the center of Pluto in p.a.
264.2 deg, and S/2005 P 2 was 2".09 from Pluto in p.a. 326.9 deg.
On May 18, the locations were 2".36 in p.a. 305.8 deg and 2".22 in
p.a. 355.5 deg. The two objects have roughly comparable brightness,
with V = 22.96 +/- 0.15 for S/2005 P 1 and V = 23.41 +/- 0.15 for
S/2005 P 2. Unique orbits cannot be calculated from the available
data, but the measured positions are consistent with nearly
circular orbits in the orbital plane of Pluto I (Charon). On this
assumption, preliminary orbital solutions yield a = 64700 +/- 850
km and P = 38.2 +/- 0.8 days for S/2005 P 1, and a = 49400 +/- 600
km and P = 25.5 +/- 0.5 days for S/2005 P 2. Examination of
archival HST ACS/HRC data taken on 2002 June 14 (PI: M. W. Buie)
shows two objects near the locations predicted by these orbits,
providing independent support for the satellite detections. A
search over the entire orbital stability zone (+/- 100" around
Pluto) does not show any other potential satellites to a limiting
magnitude of V about 27.1 (5-sigma). For additional information,
see http://www.boulder.swri.edu/plutonews.

                      (C) Copyright 2005 CBAT
2005 October 31 (8625) Daniel W. E. Green
Received on Mon 31 Oct 2005 02:29:13 PM PST