SDSS unveils a population of intrinsically faint cataclysmic variables at the minimum orbital period
SDSS unveils a population of intrinsically faint cataclysmic variables at the minimum orbital period
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DOI：
10.1111/j.1365-2966.2009.15126.x
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发表时间：
2009-05
影响因子：
4.8
通讯作者：
B. Gänsicke;M. Dillon;J. Southworth;J. Thorstensen;P. Rodríguez-Gil;A. Aungwerojwit;A. Aungwerojwit;T. Marsh;P. Szkody;S. Barros;J. Casares;D. Martino;P. J. Groot;Pasi Hakala;U. Kolb;S. Littlefair;I. G. Martínez-País;I. G. Martínez-País;G. Nelemans;M. Schreiber
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文献类型：
--
作者：
B. Gänsicke;M. Dillon;J. Southworth;J. Thorstensen;P. Rodríguez-Gil;A. Aungwerojwit;A. Aungwerojwit;T. Marsh;P. Szkody;S. Barros;J. Casares;D. Martino;P. J. Groot;Pasi Hakala;U. Kolb;S. Littlefair;I. G. Martínez-País;I. G. Martínez-País;G. Nelemans;M. Schreiber
我们讨论的137激变变量（CV），其中包括在斯隆数字巡天（SDSS）光谱数据库，并已被精确的轨道周期测量的属性。其中92个系统是SDSS的新发现，并在过去几年中进行了更详细的跟踪。45个系统先前被确定为CV，因为检测到光学爆发和/或X射线发射，随后从SDSS光谱学中重新确定。的SDSS CV的周期分布显着不同，从所有以前已知的CV，特别是它包含一个显着的积累系统的轨道周期范围80-86分钟。我们确定这一功能作为难以捉摸的“周期最小尖峰”CV人口模型预测，解决了长期存在的矛盾紧凑的二进制演化理论和观测。我们发现，这种尖峰几乎完全是由于大量的CV具有非常低的吸积活动确定的SDSS。这些系统的光谱主要由白色矮星光球的辐射所控制，并且很少或没有显示来自施主星的光谱特征，这表明它们是质量非常低的伴星。我们确定这些低光度CV在周期最小值的平均绝对星等为> = 11.6 +/- 0.7。SDSS CV样本与汉堡类星体巡天和帕洛玛绿色巡天的CV样本的比较表明，SDSS的深度是导致发现大量本质上微弱的短周期系统的关键因素。
We discuss the properties of 137 cataclysmic variables (CVs) which are included in the Sloan Digital Sky Survey (SDSS) spectroscopic data base, and for which accurate orbital periods have been measured. 92 of these systems are new discoveries from SDSS and were followed-up in more detail over the past few years. 45 systems were previously identified as CVs because of the detection of optical outbursts and/or X-ray emission, and subsequently re-identified from the SDSS spectroscopy. The period distribution of the SDSS CVs differs dramatically from that of all the previously known CVs, in particular it contains a significant accumulation of systems in the orbital period range 80-86 min. We identify this feature as the elusive 'period minimum spike' predicted by CV population models, which resolves a long-standing discrepancy between compact binary evolution theory and observations. We show that this spike is almost entirely due to the large number of CVs with very low accretion activity identified by SDSS. The optical spectra of these systems are dominated by emission from the white dwarf photosphere, and display little or no spectroscopic signature from the donor stars, suggesting very low mass companion stars. We determine the average absolute magnitude of these low-luminosity CVs at the period minimum to be > = 11.6 +/- 0.7. Comparison of the SDSS CV sample to the CVs found in the Hamburg Quasar Survey and the Palomar Green Survey suggests that the depth of SDSS is the key ingredient resulting in the discovery of a large number of intrinsically faint short-period systems.