ETHYL CYANIDE ON TITAN: SPECTROSCOPIC DETECTION AND MAPPING USING ALMA

M. A. Cordiner, M. Y. Palmer, C. A. Nixon, P. G. J. Irwin, N. A. Teanby, S. B. Charnley, M. J. Mumma, Z. Kisiel, J. Serigano, Y. -J. Kuan, Y. -L. Chuang, K. -S. Wang

Research output: Contribution to journalArticle (Academic Journal)peer-review

333 Downloads (Pure)

Abstract

We report the first spectroscopic detection of ethyl cyanide (C2H5CN) in Titan's atmosphere, obtained using spectrally and spatially resolved observations of multiple emission lines with the Atacama Large Millimeter/submillimeter Array (ALMA). The presence of C2H5CN in Titan's ionosphere was previously inferred from Cassini ion mass spectrometry measurements of C2H5CNH+. Here we report the detection of 27 rotational lines from C2H5CN (in 19 separate emission features detected at  confidence) in the frequency range 222–241 GHz. Simultaneous detections of multiple emission lines from HC3N, CH3CN, and CH3CCH were also obtained. In contrast to HC3N, CH3CN, and CH3CCH, which peak in Titan's northern (spring) hemisphere, the emission from C2H5CN is found to be concentrated in the southern (autumn) hemisphere, suggesting a distinctly different chemistry for this species, consistent with a relatively short chemical lifetime for C2H5CN. Radiative transfer models show that C2H5CN is most concentrated at altitudes  km, suggesting production predominantly in the stratosphere and above. Vertical column densities are found to be in the range (1–5) × 1014 cm−2.
Original languageUndefined/Unknown
Pages (from-to)1-7
Number of pages7
JournalAstrophysical Journal Letters
Volume800
Issue number1
DOIs
Publication statusPublished - 11 Feb 2015

Keywords

  • astro-ph.EP
  • planets and satellites: individual (Titan)
  • techniques: interferometric
  • planets and satellites: atmospheres
  • – techniques: imaging spectroscopy

Cite this