Institute of Astronomy

The chemical heritage of protoplanetary disks: new insights from ALMA and Rosetta

SpeakerTalk DateTalk Series
Catherine Walsh (Leiden University)4 February 2016Institute of Astronomy Colloquia


Protoplanetary disks are the birth sites of planets and planetesimals such as comets. Gas and ice chemistry during protoplanetary disk formation and evolution ultimately determines the composition of
planet- and comet-building material, the study of which is important for gaining insight into our origins. In recent years, our understanding of the
chemical composition and structure of nearby disks has advanced significantly. The Atacama Large Millimeter/Submillimeter Array (ALMA) has revealed the dust and gas structure of disks at (sub)mm wavelengths with unparalleled resolution, approaching size scales commensurate with that of
our own solar system (< 50 AU). In addition, the Rosetta mission is measuring the composition of comet 67P/C-G in situ with unprecedented accuracy. The cometary material is likely representative of that in the natal protoplanetary disk around the young sun.

In this seminar, I will discuss the various chemical processes which occur in protoplanetary disks and their relative importance in determining the
composition of the planet- and comet-building material. I will discuss the results of protoplanetary disk chemical models in light of recent ALMA results which probe the cooler outer disk, and I will also describe the potential formation routes and observability of so-called "complex organic molecules", species that are considered to be the precursors of prebiotic molecules, such as amino acids. I will discuss how transformational results
from the Rosetta mission are shedding new light on the heritage of comet-building material.


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