Context :

Aims : Transneptunian objects ( TNOs ) are bodies populating the Kuiper Belt and they are believed to retain the most pristine and least altered material of the solar system .
The Herschel Open Time Key Program entitled “ TNOs are Cool : A survey of the trans-Neptunian region ” has been awarded 373 hours to investigate the albedo , size distribution and thermal properties of TNOs and Centaurs .
Here we focus on the brightest targets observed by both the PACS and SPIRE multiband photometers : the dwarf planet Haumea , six TNOs ( Huya , Orcus , Quaoar , Salacia , 2002 UX25 , and 2002 TC302 ) , and two Centaurs ( Chiron and Chariklo ) .

Methods : Flux densities are derived from PACS and SPIRE instruments using optimised data reduction methods .
The spectral energy distribution obtained with the Herschel PACS and SPIRE instruments over 6 bands ( centred at 70 , 100 , 160 , 250 , 350 , and 500 \mu m ) , with Spitzer-MIPS at 23.7 and 71.4 \mu m , and with WISE at 11.6 and 22.1 \mu m in the case of 10199 Chariklo , has been modelled with the NEATM thermal model in order to derive the albedo , diameter , and beaming factor .
For the Centaurs Chiron and Chariklo and for the 1000 km sized Orcus and Quaoar , a thermophysical model was also run to better constrain their thermal properties .

Results : We derive the size , albedo , and thermal properties , including thermal inertia and surface emissivity , for the 9 TNOs and Centaurs .
Several targets show a significant decrease in their spectral emissivity longwards of \sim 300 \mu m and especially at 500 \mu m. Using our size estimations and the mass values available in the literature , we also derive the bulk densities for the binaries Quaoar/Weywot ( 2.18 ^ { +0.43 } _ { -0.36 } g/cm ^ { 3 } ) , Orcus/Vanth ( 1.53 ^ { +0.15 } _ { -0.13 } g/cm ^ { 3 } ) , and Salacia/Actea ( 1.29 ^ { +0.29 } _ { -0.23 } g/cm ^ { 3 } ) .
Quaoar ’ s density is similar to that of the other dwarf planets Pluto and Haumea , and its value implies high contents of refractory materials mixed with ices .

Conclusions :