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首页> 外文期刊>The Astrophysical journal >A CATALOG OF DIFFUSE INTERSTELLAR BANDS IN THE SPECTRUM OF HD 204827
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A CATALOG OF DIFFUSE INTERSTELLAR BANDS IN THE SPECTRUM OF HD 204827

机译：HD 204827光谱中的弥散星际带目录

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摘要

Echelle spectra of the double-lined spectroscopic binary HD 204827 were obtained on five nights, at a resolving power R = 38,000 and with a S/N = 750 near 6000 A in the final, combined spectrum. The stars show E(B - V) = 1.11 and spectral types near O9.5 Vand B0.5 III. A catalog is presented of 380 diffuse interstellar bands (DIBs) measured between 3900 and 8100 A in the stars' spectrum. The central wavelengths, the widths (FWHM), and the equivalent widths of nearly all of the bands are tabulated, along with the minimum uncertainties in the latter. The reliable removal of very weak stellar lines from the catalog, and of some stellar lines from the less severe blends with DIBs, is made generally easy by the highly variable radial velocities of both stars. The principal result of this investigation is that the great majority of the bands in the catalog are very weak and relatively narrow. Typical equivalent widths amount to a few mA, and the bandwidths (FWHM) are most often near 0.55 A. Therefore, most of these DIBs can be detected only in spectra obtained at a resolving power and a S/N at least comparable to those used here. In addition, the anomalous interstellar reddening and the very high value of the ratio N(C_2)/E(B - V) seen toward HD 204827 indicate that the physical conditions in one or more of the several interstellar clouds seen in this direction differ significantly from those found toward the prototypical DIB target HD 183143, for example. Probably primarily for these reasons, 113 of the 380 bands (30%) were not detected in four previous modern surveys of the DIBs seen in the spectra of stars other than HD 204827. No preferred wavenumber spacings among the 380 bands are reliably identified which could provide clues to the identities of the large molecules thought to cause the DIBs.
机译：在五个晚上，在最终合成光谱中，分辨力R = 38,000且S / N = 750接近6000 A，获得了双线光谱二进制HD 204827的Echelle光谱。恒星显示E（B-V）= 1.11，光谱类型接近O9.5 V和B0.5 III。列出了在星光谱中3900到8100 A之间测得的380个星际漫射带（DIB）的目录。将几乎所有波段的中心波长，宽度（FWHM）和等效宽度以及在后者中的最小不确定性列表化。由于恒星径向速度的高度变化，通常很容易从目录中可靠地删除非常弱的恒星线，以及从较不严重的与DIB的混合物中可靠地去除一些恒星线。这项调查的主要结果是，目录中的绝大多数频段都很弱并且相对较窄。典型的等效宽度为几个mA，带宽（FWHM）通常接近0.55A。因此，大多数这些DIB只能在以分辨力和S / N至少与所使用的光谱可比的光谱中检测到这里。此外，星际异常变红和朝向HD 204827观察到的N（C_2）/ E（B-V）之比的极高值表明，沿该方向观察到的几个星际云中的一个或多个的物理条件显着不同例如，从针对原型DIB的目标HD 183143中获得的收益。可能主要是由于这些原因，在以前的四次现代宇宙调查中，从HD 204827之外的恒星光谱中未发现DIB的情况下，未检测到380个波段中的113个（30％）。没有可靠地识别出380个波段中的优选波数间隔，提供被认为引起DIB的大分子身份的线索。

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