TUNA Lunch Talk:

Rachel Friesen


A Systematic Study of the Deuteration of Dense Cores in Perseus

May 22

12:10PM, Room 230, NRAO, Edgemont Road


Because of the timescales involved in the physical collapse and chemical evolution of a star-forming molecular core, it has been proposed that the abundance of a molecule relative to its deuterated isotopologue can be used as a probe of the core age. I will present results from a pointed survey of N2D+ 3-2 and 2-1 emission towards 64 starless and protostellar cores within the Perseus molecular cloud, with the goal of characterizing those factors which impact the core chemistry, while excluding cloud-to-cloud variation. We find an average N2D+/N2H+ abundance ratio, or deuterium fractionation, for all cores of 0.07. We find no significant differences between the deuterium fractionation of starless and protostellar core populations, nor between cores found in more clustered regions compared with those in more isolated environments. We additionally analysed the core deuterium fractionation against traditional probes of core evolution, including core temperature, density, and CO depletion, but find few trends of significance. Our observations contradict previous predictions of using deuteration as a simple probe of age, and suggest that deuteration levels will need to be used with care to estimate core evolutionary states.