Department of Astronomy, University of California, Los Angeles, California 90024.
Proc Natl Acad Sci U S A. 1981 Sep;78(9):5266-70. doi: 10.1073/pnas.78.9.5266.
Nebular spectral line intensities measured mostly in the optical region, but also in the IR and satellite UV (where possible), are used to derive plasma diagnostics and ionic concentrations n (X(i))/n(H(+)). Then, we use theoretical nebular models to represent as closely as possible certain excitation-sensitive line ratios of HeII/HeI, [OIII]/[OII], and [NeIII]/[NeV]. Also, we try to reproduce the line intensities themselves. These models are used as devices to allow for unobserved ionization stages. Although He, C, and N show significant variations among different nebulae, heavier elements such as O, and probably Ne, S, Cl, and Ar are more nearly constant, suggesting that progenitor stars underwent nuclear transformations in their interiors that affected C and N but not heavier elements.
主要在光学区域测量的星云谱线强度，但也在红外和卫星紫外区域（在可能的情况下）测量，用于推导等离子体诊断和离子浓度 n（X(i））/n（H(+））。然后，我们使用理论星云模型尽可能紧密地代表 HeII/HeI、[OIII]/[OII]和[NeIII]/[NeV]等激发敏感线比。此外，我们还尝试重现线强度本身。这些模型被用作设备，以允许观察到未被观测到的电离阶段。虽然 He、C 和 N 在不同的星云中表现出显著的变化，但较重的元素（如 O，可能还有 Ne、S、Cl 和 Ar）则更为恒定，这表明原恒星在其内部经历了核转化，影响了 C 和 N，但不影响较重的元素。
