Answers are grounded in this paper and cite their sources.
Spectrophotometric observations of NGC 7027 from 2.1 to 4.1 $mu$ with a resolution $delta$lambda/lambdaapprox.0.015 are reported. The spectrum is rich in features, including three hydrogen recombination lines and several unidentified features. The 2-$mu$ continuum level and the hydrogen recombination- line fluxes agree well with predictions based on the observed radio and H$beta$ fluxes.
No takes yet. Share an insight, caveat, or question.
Merrill et al. (1975) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: