A Spiral Structure in the Disk of EX Draconis on the Rise to Outburst Maximum
A Spiral Structure in the Disk of EX Draconis on the Rise to Outburst Maximum
复制标题
EX Draconis 盘中的螺旋结构正处于爆发最大值
DOI：
10.1086/312834
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
M. S. Catalan
中科院分区：
文献类型：
--
作者：
R. Baptista;M. S. Catalan
我们报道了1995年11月爆发时，矮新星EX Dra上升到最大值的高速光度测量的r波段日食映射分析。该月食图呈现出~180°方位的单臂螺旋结构，其半径从R≃0.2RL1延伸到0.43RL1（其中RL1为从圆盘中心到内拉格朗日点的距离），占月食图总通量的22%左右。螺旋结构在与双星旋转的参考系中是静止的，并且在至少五个双星轨道的时间尺度内是稳定的。日食图在上升和静止时的比较表明，EX Dra的爆发可能是由次级恒星的质量转移增强引起的。对螺旋结构性质的可能解释进行了讨论。
We report on the R-band eclipse mapping analysis of high-speed photometry of the dwarf nova EX Dra on the rise to the maximum of the 1995 November outburst. The eclipse map shows a one-armed spiral structure of ~180° in azimuth, extending in radius from R ≃ 0.2RL1 to 0.43RL1 (where RL1 is the distance from the disk center to the inner Lagrangian point), that contributes about 22% of the total flux of the eclipse map. The spiral structure is stationary in a reference frame corotating with the binary and is stable for a timescale of at least five binary orbits. The comparison of the eclipse maps on the rise and in quiescence suggests that the outbursts of EX Dra may be driven by episodes of enhanced mass transfer from the secondary star. Possible explanations for the nature of the spiral structure are discussed.