Discovery of a 176 day period in 4U 1820-30
Discovery of a 176 day period in 4U 1820-30
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4U 1820-30 中发现 176 天的周期
DOI：
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发表时间：
1983
期刊：
影响因子：
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通讯作者：
J. Terrell
中科院分区：
文献类型：
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作者：
W. Priedhorsky;J. Terrell
对X射线爆发4U1820-30(在NGC6624中)的长期X射线观测表明，它有176.4+/-1.3d的显著周期。这些数据是由船帆5B卫星上的3-12keV探测器在1969-1976年间获得的。X射线通量在整个周期内变化2倍；光曲线呈快升慢降的锯齿状，与Burster 4U 1915-05的199天光曲线非常相似。这些长周期变化可能是内在的光度变化，可能类似于矮新星的准周期爆发，也可能是与方位相关的效应，如进动吸积盘的周期性遮挡。参考文献30篇，附图3篇。
Long-term X-ray observations of the X-ray burster 4U 1820-30 (in NGC 6624) reveal a significant 176.4 +/- 1.3 day period. These data were obtained by a 3-12 keV detector on the Vela 5B satellite during the years 1969-1976. The X-ray flux varies by a factor of 2 over the cycle; the light curve, which has a sawtooth shape with fast rise and slow decline, is quite similar to the 199 day light curve of the burster 4U 1915 - 05. These long-period variations may be intrinsic luminosity changes, perhaps similar to the quasi-periodic outbursts of dwarf novae, or aspect-dependent effects, such as periodic obscuration by a precessing accretion disk. 30 references, 3 figures.