Exploring Our Solar System: Planets, Moons, and Small Rocky Bodies

Friday, 14 February 2014
Water Tower (Hyatt Regency Chicago)
Arielle Moullet , National Radio Astronomy Observatory, Charlottesville, VA
While in the last decades a large part of the observations of solar system bodies were obtained from planetary missions, the capabilities of the new ground-based (sub)millimeter and cm facilities now put this technique at the forefront of solar system exploration. Such observations allow to retrieve unique physical and chemical properties that are essential to fully characterize the individual bodies, to identify processes acting on atmospheres and surfaces, as well as to derive clues pertaining to the formation and evolution of the solar system at large.
Observations of the surface thermal continuum emission from rocky planets and small bodies are indicative of the surface and subsurface brightness temperature field, that can be modeled to derive surface properties including albedo, roughness (related to soil porosity) and thermal inertia. In addition, the combined analysis of thermal and optical observations through the radiometric method allows to determine the equivalent size of small, spatially unresolved bodies.
Amongst molecules that are often present as minor components in planetary atmospheres, several display strong (sub)millimeter rotational lines (CO, HCN, HDO, SO2,...) formed at altitudes above a few hundreds millibars. Modeling of the lines' profiles allows to derive the temperature and molecular abundance vertical profiles in atmospheric regions that are rarely probed by other techniques. When a sufficient spatial resolution is reached, the combined retrieval of temperature, wind (through Doppler-shift mapping) and composition horizontal fields is a powerful tool to constrain the global atmospheric structure, and to identify seasonal and diurnal cycles.
In this talk, I will provide an overview of the possibilities offered by (sub)mm and cm observations for the field of solar system science in the context of ALMA and EVLA. I will focus on a few topics illustrating the diversity of science cases that can be adressed: the chemical characterization of the tenuous atmosphere of Jupiter's volcanic moon Io, the mapping of Neptune's atmosphere from the deep troposphere to the stratosphere, the determination of the atmospheric wind regimes in Venus' middle atmosphere, and the retrieval of the size distribution in the Kuiper Belt.