Title: The post-Rosetta era: New perspectives on nucleus composition and the role of radio and 
IR ground-based observations

Abstract:
Do ground-based observations of cometary comae describe the nucleus composition? Rosetta 
is allowing a unique opportunity to test this hypothesis. The space-based mission is unveiling 
incredible results, and its upcoming observations throughout perihelion promise to be the most 
detailed study yet of a comet. The significance of these studies is not trivial, and the results 
stemming from the expected worldwide observational campaign will trigger great involvement, 
including professional astrophysicists, amateur astronomers and the public. 

To enhance the outcome from past, present and future space-based missions, ground-based 
observations are a critical supporting strategy to put spacecraft results in context. It is through 
such synergy that we can establish the true means for quantitative detections on the study of 
comets, thanks to improved observational strategies, data analysis techniques and instrument 
performance.

High-resolution spectroscopy at radio and infrared wavelengths provides measurements of the 
global properties of release and composition that can give context for Rosetta’s local 
measurements, allowing us to compare direct measurements of the nucleus to those inferred 
from ground-based observations of the coma. Indeed, extrapolation of the local measurements 
from the Rosetta spacecraft and ground-based observations can reveal essential coma 
information, including gas temperatures, production rates, and outgassing patterns as observed 
from the ground. Moreover, Rosetta''s lander Philae will measure the composition of the nucleus 
and that close to the surface. In this presentation, I will discuss unique aspects of cometary 
studies that can be solely achieved by ground-based radio and IR observations of the cometary 
comae, as well as benchmarks and challenges that we might need to address as a result of the 
Rosetta findings.

Acknowledgements: NASA's Planetary Astronomy, Planetary Atmospheres and Astrobiology 
Programs, and the National Science Foundation.


Co-authors:
M.J. Mumma, G.L. Villanueva, B.P. Bonev, S.B. Charnley, M.A. Cordiner, M.A. DiSanti, E.L. 
Gibb, S.N. Milam