TY - JOUR
T1 - "tNOs are cool"
T2 - A survey of the trans-Neptunian region: XI. A Herschel-PACS view of 16 centaurs
AU - Duffard, R.
AU - Pinilla-Alonso, N.
AU - Santos-Sanz, P.
AU - Vilenius, E.
AU - Ortiz, J. L.
AU - Mueller, T.
AU - Fornasier, S.
AU - Lellouch, E.
AU - Mommert, M.
AU - Pal, A.
AU - Kiss, C.
AU - Mueller, M.
AU - Stansberry, J.
AU - Delsanti, A.
AU - Peixinho, N.
AU - Trilling, D.
N1 - Funding Information: R.D. acknowledges the support of MINECO for his Ramon y Cajal Contract. N.P.A’s work was supported by MINECO through a fellowship of the Juan de la Cierva program. A.P. acknowledges grant LP2012-31. N.P.A. and P. S.-S. acknowledge support by contract AYA2011-30106-C02-01. The work of C.K. has been supported by the Hungarian Space Office and the European Space Agency through contract PECS-98073, the K-104607 grant of the Hungarian Research Fund (OTKA), and the Bolyai Research Fellowship of the Hungarian Academy of Sciences. EV acknowledges the support of the German DLR project number 50 OR 1108. This work is based (in part) on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. N.P. acknowledges funding by the Gemini-Conicyt Fund, allocated to project No. 32120036.
PY - 2014/4
Y1 - 2014/4
N2 - Context. Centaurs are the transitional population between trans-Neptunian objects (TNOs) and Jupiter-family comets. Their physical properties provide an insight into TNO properties, but only under restricted conditions since Centaurs are closer to the Sun and Earth. For this reason it is possible to access the smaller ones, which is more difficult to do with the TNO population. Aims. The goal of this work is to characterize a set of 16 Centaurs in terms of their size, albedo, and thermal properties. We study the correlations, for a more extended sample obtained from the literature, of diameter, albedo, orbital parameters, and spectral slopes. Methods. We performed three-band photometric observations using Herschel-PACS and used a consistent method for the data reduction and aperture photometry of this sample to obtain monochromatic flux densities at 70, 100, and 160 μm. Additionally, we used Spitzer-MIPS flux densities at 24 and 70 μm when available. We also included in our Centaur sample scattered disk objects, a dynamical family of TNOs, using results previously published by our team, and some Centaurs observed only with the Spitzer-MIPS instrument. Results. We have determined new radiometric sizes and albedos of 16 Centaurs. The first conclusion is that the albedos of Centaur objects are not correlated with their orbital parameters. Similarly, there is no correlation between diameter and orbital parameters. Most of the objects in our sample are dark (pv< 7%) and most of them are small (D< 120 km). However, there is no correlation between albedo and diameter, in particular for the group of small objects as albedo values are homogeneously distributed between 4 to 16%. The correlation with the color of the objects showed that red objects are all small (mean diameter 65 km), while the gray ones span a wide range of sizes (mean diameter 120 km). Moreover, the gray objects tend to be darker, with a mean albedo of 5.6%, compared with a mean of 8.5% (ranging from 5 to 15%) for the red objects.
AB - Context. Centaurs are the transitional population between trans-Neptunian objects (TNOs) and Jupiter-family comets. Their physical properties provide an insight into TNO properties, but only under restricted conditions since Centaurs are closer to the Sun and Earth. For this reason it is possible to access the smaller ones, which is more difficult to do with the TNO population. Aims. The goal of this work is to characterize a set of 16 Centaurs in terms of their size, albedo, and thermal properties. We study the correlations, for a more extended sample obtained from the literature, of diameter, albedo, orbital parameters, and spectral slopes. Methods. We performed three-band photometric observations using Herschel-PACS and used a consistent method for the data reduction and aperture photometry of this sample to obtain monochromatic flux densities at 70, 100, and 160 μm. Additionally, we used Spitzer-MIPS flux densities at 24 and 70 μm when available. We also included in our Centaur sample scattered disk objects, a dynamical family of TNOs, using results previously published by our team, and some Centaurs observed only with the Spitzer-MIPS instrument. Results. We have determined new radiometric sizes and albedos of 16 Centaurs. The first conclusion is that the albedos of Centaur objects are not correlated with their orbital parameters. Similarly, there is no correlation between diameter and orbital parameters. Most of the objects in our sample are dark (pv< 7%) and most of them are small (D< 120 km). However, there is no correlation between albedo and diameter, in particular for the group of small objects as albedo values are homogeneously distributed between 4 to 16%. The correlation with the color of the objects showed that red objects are all small (mean diameter 65 km), while the gray ones span a wide range of sizes (mean diameter 120 km). Moreover, the gray objects tend to be darker, with a mean albedo of 5.6%, compared with a mean of 8.5% (ranging from 5 to 15%) for the red objects.
KW - Kuiper belt: general
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U2 - 10.1051/0004-6361/201322377
DO - 10.1051/0004-6361/201322377
M3 - Review article
SN - 0004-6361
VL - 564
JO - Astronomy and astrophysics
JF - Astronomy and astrophysics
M1 - A92
ER -