Confirmation of the first detection of HNC on Titan

Abstract

Herschel/HIFI detection of HNC at 543.897 GHz on Titan in June 2010 were reported by [1]. In 2011, as part of the Herschel/HSSO key program [2], we have performed additional observations I) at 543.897 GHz with the HIFI heterodyne receiver onboard of the Herschel spatial observatory II) with the IRAM radiotelecope at 271.9 GHz, III) with the SMA interferometer at 362.6 GHz. Observations of HCN has been also performed at the same time that those of HNC. All these observations detected HNC, and therefore confirm the presence of HNC on Titan atmosphere. A detailled study of the relative line intensities and FWHM is ongoing. With the combination of all these detected HNC rotational lines, we expect to constrain the vertical distribution of HNC and to derive the HNC/HCN ratio. This analysis will be presented, as well as a comparison with vertical profiles expected from photochemical models.