"TNOs are Cool": A survey of the trans-Neptunian region X. Analysis of classical Kuiper belt objects from Herschel and Spitzer observations

• Main Authors: Vilenius, E, Kiss, C, Müller, T, Mommert, M, Santos-Sanz, P, Pál, A, Stansberry, J, Mueller, M, Peixinho, N, Lellouch, E, Fornasier, S, Delsanti, A, Thirouin, A, Ortiz, J. L, Duffard, R, Perna, D, Henry, F
• Format: Journal Article
• Language: English
• Published: 25-03-2014
• Subjects: Physics - Earth and Planetary Astrophysics
• DOI: 10.48550/arxiv.1403.6309

The classical Kuiper belt contains objects both from a low-inclination,
presumably primordial, distribution and from a high-inclination dynamically
excited population. Based on a sample of classical TNOs with observations at
thermal wavelengths we determine radiometric sizes, geometric albedos and
thermal beaming factors as well as study sample properties of dynamically hot
and cold classicals. Observations near the thermal peak of TNOs using infra-red
space telescopes are combined with optical magnitudes using the radiometric
technique with near-Earth asteroid thermal model (NEATM). We have determined
three-band flux densities from Herschel/PACS observations at 70.0, 100.0 and
160.0 $\mu$m and Spitzer/MIPS at 23.68 and 71.42 $\mu$m when available. We have
analysed 18 classical TNOs with previously unpublished data and re-analysed
previously published targets with updated data reduction to determine their
sizes and geometric albedos as well as beaming factors when data quality
allows. We have combined these samples with classical TNOs with radiometric
results in the literature for the analysis of sample properties of a total of
44 objects. We find a median geometric albedo for cold classical TNOs of 0.14
and for dynamically hot classical TNOs, excluding the Haumea family and dwarf
planets, 0.085. We have determined the bulk densities of Borasisi-Pabu (2.1
g/cm^3), Varda-Ilmare (1.25 g/cm^3) and 2001 QC298 (1.14 g/cm^3) as well as
updated previous density estimates of four targets. We have determined the
slope parameter of the debiased cumulative size distribution of dynamically hot
classical TNOs as q=2.3 +- 0.1 in the diameter range 100<D<500 km. For
dynamically cold classical TNOs we determine q=5.1 +- 1.1 in the diameter range
160<D<280 km as the cold classical TNOs have a smaller maximum size.