EVLA Observations of the Largest TNOs

Abstract

Despite the importance of understanding TNOs in the context of solar system formation and evolution, the physical properties of these bodies are relatively poorly known. Though masses are known for at least those with satellites, their radii are poorly constrained, making estimates of such a fundamental quantity as density highly uncertain. Little is also known about the surface temperatures of these bodies; equilibrium with solar radiation is usually assumed. Long wavelength thermal emission observations are a powerful way to constrain such quantities more accurately. They additionally sample below the surface (to roughly 10 wavelengths), yielding information about thermal and structure characteristics to that depth. Unfortunately, long wavelength emission is weak and has only been done successfully at millimeter wavelengths for a few of the largest TNOs. The EVLA is the next generation centimeter wavelength telescope, building on the tremendous success of the VLA. The main improvement is an eventual factor of 10 better sensitivity. Observations at a wavelength of 1 cm of the TNOs 2002 TC302, Makemake, Quaoar, and Eris, along with the Pluto system and Triton have been approved for the EVLA, and we will present all data taken on these bodies (the Pluto system will not be observed until spring 2011, when Pluto and Charon can be resolved from each other). This is part of a longer term program to measure the microwave emission spectrum of these bodies from roughly 0.5 mm to 5 cm using both the EVLA and ALMA.