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arXiv 1208.0380astro-ph.SR
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新星“He/N”和“Fe II”谱类的起源

Origin of the `He/N' and `Fe II' Spectral Classes of Novae

Robert Williams

摘要:

爆发后新星的光谱显示无论是他+N或Fe II线作为最突出的非巴耳末线在最大光。光谱诊断表明物理条件的“He/N”光谱是一致的,其起源在白矮星(WD)喷出物,而“Fe II”光谱点,他们的形成在一个大的circumbinary信封的气体,其起源是第二颗星。两种类型的光谱中哪一种占主导地位的决定性参数可以是二元质量比Msec/MWD。新星被观察到的“混合”的对象,这两类光谱顺序出现的比例增加,解释了在爆发后下降的两个发射区域中的参数变化。我们认为,大多数新星可能是混合动力车,显示两种类型的光谱在下降。发射线强度比O I λ8446/λ7773被认为是一个很好的密度诊断的喷出物,并提出了一个发现的清单,在最近的光谱调查的新星发射线确定为未来的线识别工作的援助。

英文摘要:

The spectra of postoutburst novae display either He+N or Fe II lines as the most prominent non-Balmer lines at maximum light. Spectral diagnostics indicate physical conditions for 'He/N' spectra that are consistent with their origin in the white dwarf (WD) ejecta, whereas 'Fe II' spectra point to their formation in a large circumbinary envelope of gas whose origin is the secondary star. A determining parameter for which of the two types of spectra predominates may be the binary mass ratio Msec/MWD. The increasing fraction of novae that are observed to be 'hybrid' objects, where both classes of spectra appear sequentially, is explained by changing parameters in the two emitting regions during the postoutburst decline. We argue that most novae may be hybrids that show both types of spectra during decline. The emission line intensity ratio O I λ8446/λ7773 is suggested as a good density diagnostic for the ejecta, and a finding list of emission lines identified in recent spectroscopic surveys of novae is presented as an aid to future line identification work.

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