Organic chemistry around young high-mass stars: Observational and theoretical / Dr 
Veronica Allen (NASA Goddard Space Flight Center)
	
In the study of high-mass star formation, hot cores are empirically defined stages 
where chemically rich emission is detected toward a high-mass protostar. It is unknown 
whether the physical origin of this emission is a disk, inner envelope, or outflow 
cavity wall and whether the hot core stage is common to all massive stars. With the 
advent of the highly sensitive sub-millimeter interferometer, ALMA, the ability to 
chemically characterize high-mass star-forming regions other than Orion has become 
possible. These sensitive high-resolution observations have opened up opportunities to 
find small scale variations in young protostellar sources.

Taking a two part approach, we investigate the chemistry of the hot cores within 
star-forming region G35.20-0.74N (G35.20) using high spatial resolution (~1000 AU) 
Cycle 0 ALMA observations and rate-equation-based chemical models. The observational 
analysis uncovered an interesting asymmetry in the distribution of the Nitrogen-bearing 
species (especially those with the CN-group) within G35.20 B. This was unexpected as 
this source contains a candidate Keplerian disk and such a segregation in chemistry is 
unexpected because of the short dynamical time-scale of the system. The first part of 
my talk outlines the observational result and results of our follow-up chemical 
modelling to determine a cause for small scale chemical segregation, and therefore the 
usefulness of complex cyanides as chemical clocks.

In the second part of my talk, I detail the results of a second study where I observe 
several different young stars and how the extent and movement of formamide (NH2CHO) in 
the gas surrounding the stars compares to its two possible parent species. This is 
important astrochemical work because there is debate about whether formamide is formed 
in ice and melts off once it becomes warm (from one parent) or in already warm gas 
(from the other parent). Formamide itself is important because it may lead to amino 
acids and other important molecules of life.