P. Santos-Sanz, E. Lellouch, S. Fornasier, C. Kiss, A. Pal, T. G. Müller, E. Vilenius, J. Stansberry, M. Mommert, A. Delsanti, M. Mueller, N. Peixinho, F. Henry, J. L. Ortiz, A. Thirouin, S. Protopapa, R. Duffard, N. Szalai, T. Lim, C. Ejeta, P. Hartogh, A. W. Harris, M. Rengel
Physical characterization of Trans-Neptunian objects, a primitive population
of the outer solar system, may provide constraints on their formation and
evolution. The goal of this work is to characterize a set of 15 scattered disk
(SDOs) and detached objects, in terms of their size, albedo, and thermal
properties. Thermal flux measurements obtained with the Herschel-PACS
instrument at 70, 100 and 160 \mu m, and whenever applicable, with Spitzer-MIPS
at 24 and 70 \mu m, are modeled with radiometric techniques, in order to derive
the objects' individual size, albedo and when possible beaming factor. Error
bars are obtained from a Monte-Carlo approach. We look for correlations between
these and other physical and orbital parameters. Diameters obtained for our
sample range from 100 to 2400 km, and the geometric albedos (in V band) vary
from 3.8 % to 84.5 %. The unweighted mean V geometric albedo for the whole
sample is 11.2 % (excluding Eris); 6.9 % for the SDOs, and 17.0 % for the
detached objects (excluding Eris). We obtain new bulk densities for three
binary systems: Ceto/Phorcys, Typhon/Echidna and Eris/Dysnomia. Apart from
correlations clearly due to observational bias, we find significant
correlations between albedo and diameter (more reflective objects being
bigger), and between albedo, diameter and perihelion distance (brighter and
bigger objects having larger perihelia). We discuss possible explanations for
these correlations.
View original:
http://arxiv.org/abs/1202.1481
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