InterCat seminar

Speaker: Gabi Wenzel, Brett McGuire group, MIT Chemistry, Massachusetts, USA

Title: Discovery of three cyanopyrene isomers in TMC-1
 

Abstract:

Polycyclic aromatic hydrocarbons (PAHs) are expected to be the most abundant class of organic molecules in space; however, their lifecycle in the interstellar medium (ISM) is not well understood. Our recent discovery of three isomers of CN-functionalized pyrene, a 4-ring PAH, in GOTHAM observations of the dense cloud TMC-1 suggests that pyrene could account for up to 0.1% of the carbon budget in dense clouds, the birth sites of stars and planets. The three isomers, 1-, 2- and 4-cyanopyrene, are present in an abundance ratio of ∼2:1:2, which mirrors the number of equivalent sites available for CN addition. From this we constrain the abundance of interstellar pyrene, a PAH that cannot be directly detected by radio astronomy. The high abundance of pyrene relative to other small aromatics identified so far in TMC-1 is difficult to explain using currently proposed chemical mechanisms and further observations will be required to unravel the (aromatic) chemistry at play in the dense ISM.