It’s icy out there – Bulk Processing in Outer Solar System Minor Bodies

Gal Sarid, Florida Space Institute, University of Central Florida
Physical Sciences Building 160/161
September 9, 2016, 4:30-6:00pm

Abstract: The outer Solar System hosts a vast population of small bodies, considered to be primitive remnants from the planet-formation epoch. The nature of these icy-rocky bodies, ranging in size from sub-km comets to dwarf-planet Plutos, is one of the current central themes in planetary science and exploration. Investigation of primitive bodies addresses questions about the initial stages, conditions, and processes during solar system formation, and the sources of organic and volatile material to the planets. With the on-going development of observing techniques and instruments, there are several potential analogs to our own diverse population of minor bodies littering other circum-stellar systems. These serve as signposts for early formation, or late evolution, of potentially habitable environments. Recent observations have revealed that many large trans-Neptunian objects exhibit surface spectral features of crystalline water ice and more volatile constituents, such as methane or hydrated ammonia. Comets have been known to host a vast grid of C-H-O-N-S compounds, from coma measurements, and have been recently observed to have under-dense bulk interiors and very complex surfaces. Cometary-like objects, most probably owing their out-gassing activity to sublimation of volatile ices, have been observed in recent years in some unexpected places, such as the outer planet Centaur region and within the main belt of asteroids. Early thermal and collisional processes affected all the planetesimal populations mentioned, but to varying degrees of alteration, depending on initial composition, time scale of physical-chemical reactions and local dynamics.

In my talk I will introduce several evolution modeling approaches, relevant for some of these volatile rich objects, and the accompanying results, which refer to the thermal, physical and chemical evolution of the bulk body and its surface composition. We will discuss what we can glean from considering multi parameter physical models in combination with recent physical measurements (attained either through space missions, groundbased observations or laboratory studies).