What do Carbon and Nitrogen Isotope Abundance Ratios tell us on comet origin?


Emmanuël Jehin
European Southern Observatory, Casilla 19001, Santiago, Chile

Did comets form during the same events that gave birth to the Sun and planets?
Are they more primitive bodies that record pre-solar history ?
Isotopic ratios are one of the most important clues to understand the chemical and physical 
processing of the solar systemmaterial since its formation. Their measurements in comets are 
then excellently suited to probe the link between comets and the origin of the solar system. 
We will review the measurements of the stable isotopes of the light elements and focus on 
the Carbon and Nitrogen isotopic ratios that we have measured from the CN (0,0) violet band 
in many cometary comas since C/Hale-Bopp, ten years ago. The prospects for future 
measurements from space missions and ground-base observatories will be presented.