The UV spectra of all "weak emission line central stars of planetary nebulae" (WELSs) with available IUE data are presented and discussed. We performed line identifications and equivalent-width and flux measurements for several features in the spectra. We found that the WELSs can be divided into three different groups regarding their UV spectra: (1) strong P Cygni profiles (mainly in C IV λ1549), (2) weak P Cygni features, and (3) absence of P Cygni profiles. The last group encompasses stars with a featureless UV spectrum or with intense emission lines and a weak continuum, which are most likely of nebular origin. We have measured wind terminal velocities for all objects presenting P Cygni profiles in N V λ1238 and/or C IV λ1549. The results obtained were compared to the UV data of the two prototype stars of the [WC]-PG 1159 class, namely, A30 and A78. For WELSs presenting P Cygni features, most of the terminal velocities fall in the range of ~1000-1500 km s-1, while [WC]-PG 1159 stars possess much higher values, of ~3000 km s-1. The [WC]-PG 1159 stars are characterized by intense, simultaneous P Cygni emissions in the ~1150-2000 ? interval of N V λ1238, O V λ1371, and C IV λ1549. In contrast, we found that O V λ1371 is very weak or absent in the WELS spectra. On the basis of the UV spectra alone, our findings indicate that [WC]-PG 1159 stars are distinct from the WELSs, contrary to previous claims in the literature.
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机译：介绍和讨论了所有“行星状星云的弱发射线中心星”（WELSs）的紫外线光谱以及可用的IUE数据。我们对光谱中的几个特征进行了线识别以及等效宽度和通量测量。我们发现，就其紫外光谱而言，WELS可分为三类：（1）强P Cygni轮廓（主要在C IVλ1549中），（2）弱P Cygni特征和（3）不存在P Cygni轮廓。最后一组包括具有无特征的UV光谱或强烈的发射线和弱的连续谱的恒星，这些恒星很可能来自星云。我们测量了所有在N Vλ1238和/或C IVλ1549中呈现P Cygni轮廓的物体的风速。将获得的结果与[WC] -PG 1159类的两个原型恒星，即A30和A78的紫外线数据进行比较。对于具有P Cygni特征的WELS，大多数终极速度在〜1000-1500 km s-1范围内，而[WC] -PG 1159星具有更高的值，约为3000 km s-1。 [WC] -PG 1159星的特征是在〜1150-2000？期间同时发生强烈的P Cygni辐射。 N Vλ1238，OVλ1371和C IVλ1549的间隔。相反，我们发现在WELS光谱中O Vλ1371非常弱或不存在。仅根据紫外线光谱，我们的发现表明[WC] -PG 1159星与WELS不同，这与文献中先前的主张相反。
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