Infrared Properties of Cataclysmic Variables in the 2 Micron All-Sky Survey Second Incremental Data Release
Infrared Properties of Cataclysmic Variables in the 2 Micron All-Sky Survey Second Incremental Data Release
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2微米全天巡天第二次增量数据发布中灾难性变星的红外特性
DOI：
10.1086/324499
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
Steward ObservatoryUniversity of Arizona
中科院分区：
文献类型：
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作者：
D. Hoard;S. Wachter;L. L. Clark;Timothy P. Bowers Cerro Tololo Inter;San Diego State University;Steward ObservatoryUniversity of Arizona
激变变星（CV）“传统上”主要在短波长下观测到，因为吸积产生的光度在紫外光中达到峰值，主导了大多数系统的辐射能量。因此，对它们的红外（IR）特性知之甚少。研究红外线中的CV将有助于理解预期在这些波长下辐射的关键系统组件，例如冷的外盘、吸积流和次级星星。我们编制了2微米全天巡天（2 MASS）第二次增量数据发布的天空覆盖范围内所有激变变量的近红外J，H和Ks波段测光。该数据包括251个激变变星，它们具有可靠的近红外对应物，并且在三个近红外波段中的一个或多个波段中的光度测量信噪比大于10。除了包含2 MASS数据的表格外，我们还为选定的系统提供了一组近红外发现图表。2 MASS测光和各种文献来源的近红外测光的激变变量之间的比较显示出良好的协议后，允许光度系统的差异和激变变量的内在变化。我们的大部分分析包括近红外颜色的主要激变类的彩色图的探索。分析结果表明：（1）爆发期和平静期的矮新星在色图上占据不同的区域，（2）类新星的CV（和爆发中的矮新星）具有类似于F-K主序星的颜色，尽管这并不意味着它们有F-K型的次级星;（3）极星和中间极星在它们的色图中也占据着不同的区域，大多数极星的颜色基本上与晚（M0+）主序星无法区分;（4）新星的年龄与颜色之间没有很强的相关性，但许多老的新星（爆发后>75年）颜色类似于F-K主序星;（5）在所有的颜色-颜色图中，都有不寻常的和无法解释的数据点的轨迹，需要在IR中进一步研究。除了极线的情况外，激变变星的近红外测光并不孤立它们的二级恒星的光度贡献。一般来说，激变变星的近红外线颜色会明显地、系统地偏蓝，偏离预期在其轨道周期的二级星星的光谱类型。这种近红外光的蓝色污染几乎肯定来自吸积过程。对于少数系统，它们的近红外颜色比预期的次级星星在轨道周期更红。一个可以解释部分（但不是全部）红色过剩激变变星的效应是演化的次级星星的存在。我们认为，这也可能是由显著吸积盘的冷外部区域的光度贡献造成的。在更高倾角的星系中，至少有一种微弱的红色趋势（在这种情况下，盘缘最明显，而热的内部区域最模糊）支持这一假设。
Cataclysmic variables (CVs) have "traditionally" been observed primarily at short wavelengths because accretion-generated luminosity, which peaks in the optical-ultraviolet, dominates the radiated energy of most systems. Hence, relatively little is known about their infrared (IR) properties. Investigating CVs in the IR will contribute to the understanding of key system components that are expected to radiate at these wavelengths, such as the cool outer disk, accretion stream, and secondary star. We have compiled the near-IR J, H, and Ks band photometry of all cataclysmic variables contained in the sky coverage of the Second Incremental Data Release of the 2 Micron All Sky Survey (2MASS). This data comprises 251 cataclysmic variables with reliably identified near-IR counterparts and S/N > 10 photometry in one or more of the three near-IR bands. In addition to tables containing the 2MASS data, we present a set of near-IR finding charts for selected systems. A comparison between the 2MASS photometry and various literature sources of near-IR photometry of cataclysmic variables shows good agreement after allowing for differences in photometric systems and the intrinsic variability of cataclysmic variables. The bulk of our analysis consists of an exploration of near-IR color-color diagrams of the main cataclysmic variable classes. Results from this analysis include: (1) dwarf novae in outburst and quiescence occupy distinct regions of their color-color diagram; (2) nova-like CVs (and dwarf novae in outburst) have colors similar to F-K main-sequence stars, although this does not imply that they have F-K type secondary stars; (3) polars and intermediate polars also occupy distinct regions in their color-color diagram, with most polars having colors essentially indistinguishable from late (M0+) main-sequence stars; (4) there is no strong correlation between age and color for novae, except that many old novae (>75 yr since outburst) have colors similar to F-K main-sequence stars; and (5) there are unusual and unexplained loci of data points in all the color-color diagrams that warrant further investigation in the IR. Except in the case of the polars, near-IR photometry of cataclysmic variables does not isolate the luminosity contribution of their secondary stars. In general, the near-IR colors of cataclysmic variables are significantly and systematically offset blueward of the spectral type of secondary star expected at their orbital periods. This blue contamination of the near-IR light almost certainly originates from the accretion process. For a few systems, their near-IR color is redder than the secondary star expected at their orbital period. One effect that can explain some, but not all, of the red-excess cataclysmic variables is the presence of an evolved secondary star. We suggest that this can also be caused by the luminosity contribution of the cool outer regions of prominent accretion disks. There is at least a weak trend of redder color in higher inclination systems (in which the disk rim would be most visible and most obscure the hot inner region) that supports this hypothesis.