Data: 10.11.2022

Palestrante: Dr. Pablo Santos-Sanz (Instituto de Astrofísica de Andalucía)

Link: https://youtu.be/KsguDS8fnAs

Resumo: Physical knowledge of trans-Neptunian objects (TNOs) and Centaurs has improved in recent years thanks to more sensitive observations of their thermal emission with the Spitzer and Herschel space telescopes. Thermal emission from TNOs/Centaurs has also been measured with ALMA, WISE, and other ground- and space-based radio facilities. These data allow, by means of thermal or thermophysical models, to obtain the diameters and albedos of these bodies with uncertainties of ~10% in diameters and ~20% in albedos. Thermal properties such as thermal inertia or surface roughness can also be obtained. In total, we have thermal measurements for ~180 TNOs/Centaurs, for which we have obtained equivalent diameters, albedos, and thermal properties. On the other hand, stellar occultations produced by TNOs and Centaurs are a very direct and elegant way to obtain sizes (with a few kilometers of uncertainty), shapes, and albedos of these bodies from the timing of a star disappearing and reappearing behind the object’s limb. In the last decade, it has been possible to predict and observe stellar occultations by TNOs/Centaurs thanks to the better knowledge of their orbits and the improvement of stellar positions from the available stellar catalogs. To date, stellar occultations produced by ~50 TNOs/Centaurs have been observed, obtaining an accurate determination of their sizes and albedos. Thermal emission is available for most of these ~50 objects. There is a clear synergy between thermal measurements and stellar occultations and it is possible to combine the results of both techniques to obtain a better physical and thermal characterization of these bodies.