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首页> 外文期刊>The Astrophysical journal >WZ Sagittae: FUSE Spectroscopy of the 2001 Outburst*
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WZ Sagittae: FUSE Spectroscopy of the 2001 Outburst*

机译:WZ射手座:2001年爆发的保险丝光谱*

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The short-period cataclysmic variable WZ Sge underwent its first dwarf nova outburst in 23 years in 2001 July. Here we describe 905-1187 ? spectra obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) during the outburst and within the first few months after the outburst. The first spectrum, obtained about 7 days after the outburst began and 6.4 days past optical maximum, is dominated by a broad (50-60 ? equivalent width) feature due to O VI and can be characterized in terms of emission from a highly inclined disk modulated by the effects of a highly ionized wind. WZ Sge is fainter in later observations (starting about 45 days after optical maximum) and increasingly "red" in the far ultraviolet. The spectral shape increasingly resembles that expected from a metal-enriched white dwarf photosphere, although it seems likely that some disk contribution remains at least through the second FUSE observation, when the visible light curve showed the system to be undergoing a rebrightening event. The absorption lines observed on September 29 and in early November, when the visible light curve was in a fairly steady decline toward quiescence, are narrow, with widths (FWHM) of the order of 0.7-1.3 ? (200-400 km s-1). The most natural explanation for these spectra is that the continuum arises from a relatively massive, slowly rotating white dwarf and that the lines are created by a combination of metals in the atmosphere and absorbing material along the line of sight to the white dwarf. If the white dwarf has log g = 8.5, then the white dwarf cooled from ~25,000 K on September 29 to 23,000 K in early November.
机译:短周期的变质变量WZ Sge于2001年7月进行了23年以来的首次矮新星爆发。在这里我们描述905-1187吗?在爆发期间以及爆发后的前几个月内,使用远紫外光谱浏览器(FUSE)获得的光谱。第一个光谱是在爆发开始后约7天和光学最大值之后6.4天获得的,其主要特征是O VI引起的宽幅特征(等效宽度为50-60?),可以用高倾斜盘的发射来表征通过高度电离的风的作用进行调制。 WZ Sge在较晚的观测中(从光学最大值后约45天开始)较弱,并且在远紫外线中逐渐“变红”。光谱形状越来越类似于富金属的白矮星光球所期望的光谱形状,尽管当可见光曲线显示该系统正在发生再增亮事件时,至少通过第二次FUSE观察似乎仍有一些圆盘贡献。在9月29日和11月初观察到的吸收线很窄,当可见光曲线向静止状态逐渐下降时,其吸收线窄,宽度(FWHM)约为0.7-1.3?。 (200-400公里s-1)。这些光谱的最自然的解释是,连续体是由一个相对较大的,缓慢旋转的白矮星产生的,并且这些线是由大气中的金属结合并沿视线吸收材料到白矮星而形成的。如果白矮星的log g = 8.5,那么白矮星将从9月29日的〜25,000 K冷却至11月初的23,000K。

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