The Remarkable Molecular Content of Planetary Nebulae

D. R. Schmidt, Lucy M Ziurys

Research output: Contribution to journalArticlepeer-review


In order to further define the molecular content of planetary nebulae (PNe), we have conducted searches for HCN, HCO+, HNC, and CCH at millimeter wavelengths in a sample of seventeen PNe using the new 12 m and Sub-Millimeter Telescopes of the Arizona Radio Observatory (ARO). HCN and HCO+ were identified in 75% of the PNe, with corresponding fractional abundances of f(HCN/H2) ~ 0.1-9.1 × 10-7 and f(HCO+/H2) ~ 0.04-7.4 × 10-7. HNC was subsequently identified in twelve PNe with f(HNC/H2) ~ 0.02-2.2 × 10-7. The [HCN]/[HNC] ratio was found to be ~1-8 in nebulae observed. CCH was also detected in eight PNe. The abundances for all molecules were found to remain relatively constant with nebular age across 10,000 years, in contrast to model predictions. They are also 10-100 greater than those observed in diffuse clouds, and suggest that molecular material from PNe seed the diffuse ISM.

Original languageEnglish (US)
Pages (from-to)218-224
Number of pages7
JournalProceedings of the International Astronomical Union
Issue numberS332
StatePublished - 2017


  • ISM: molecules - planetary nebulae: general - radio lines: ISM

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Astronomy and Astrophysics
  • Nutrition and Dietetics
  • Public Health, Environmental and Occupational Health
  • Space and Planetary Science


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