Sampling molecular gas in the Helix planetary nebula: Variation in HNC/HCN with UV flux
Sampling molecular gas in the Helix planetary nebula: Variation in HNC/HCN with UV flux
Observations of molecular clouds, prestellar cores, and protoplanetary disks have established that the HNC/HCN ratio may be a potent diagnostic of molecular gas physical conditions. The processes that govern the relative abundances of these molecules nevertheless remain poorly understood. We seek to exploit the wide range of UV irradiation strengths …