Paper: astro-ph/0511837
Date: Wed, 30 Nov 2005 19:37:52 GMT (124kb)

Title: New Constraints on Additional Satellites of the Pluto System

Authors: A.J. Steffl, M.J. Mutchler, H.A. Weaver, S.A.Stern, D.D. Durda, D.
Terrell, W.J. Merline, L.A. Young, E.F. Young, M.W. Buie, and J.R. Spencer

Comments: 18 pages including 4 figures
\\
Observations of Pluto and its solar-tidal stability zone were made using the
Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST) on UT
2005 May 15 and UT 2005 May 18. Two small satellites of Pluto, provisionally
designated S/2005 P 1 and S/2005 P 2, were discovered and are reported by
(Weaver et al. 2005). These observations also provide strong constraints on the
existence of any additional satellites of Pluto. We place a 90%-confidence
lower limit of V=26.2 (V=27.1 for a 50%-confidence lower limit) on the
magnitude of undiscovered satellites >5" from Pluto. Assuming an albedo of
p_v=0.04 (similar to cometary nucleii and a reasonable lower limit), this
corresponds to a limiting diameter of 37 km at 90%-confidence (25 km at
50-confidence). For an assumed albedo similar to Charon, i.e p_v=0.38, the
magnitude limit corresponds to a limiting diameter of 12 km at 90%-confidence
(8 km at 50%-confidence). At distances <5" from Pluto, scattered light from
both Pluto and Charon degrades the sensitivity of our search, such that at 1.7"
from Pluto the 50%-confidence magnitude limit is V=25.3, corresponding to a
limiting diameter of 57 km for an object with p_v=0.04.

\\ ( http://arXiv.org/abs/astro-ph/0511837 , 124kb)