Near-infrared observations of AFGL 618. II. The atomic spectrum

Douglas M. Kelly, William B. Latter, G. H. Rieke

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


We measured the 0.84-1.35 μm spectrum for the eastern lobe and the 0.40-0.68 μm spectra for both lobes of the proto - planetary nebula AFGL 618. These rich emission spectra are highlighted by strong forbidden lines. We have compiled an extensive line list from these spectra, including many identifications in the poorly explored 1.0-1.35 μm region. The atomic line ratios indicate that there is both high- and low-temperature gas in the lobes. The apparently shock-excited hotter gas has an electron temperature of Te ≈ 25,000 K and an electron density of ne ≈ 8000 cm-3; the cooler gas has Te ≈ 10,000 K and ne ≈ 1600 cm-3. We used line strengths to determine the filling factors of these two components and found that the cool component fills most of the visible lobes. We compare our results with previous work.

Original languageEnglish (US)
Pages (from-to)174-184
Number of pages11
JournalAstrophysical Journal
Issue number1
StatePublished - Aug 10 1992


  • ISM: individual (AFGL 618)
  • Infrared: general
  • Line: identification
  • Planetary nebulae: individual (AFGL 618)

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Near-infrared observations of AFGL 618. II. The atomic spectrum'. Together they form a unique fingerprint.

Cite this