arXiv 0709.15082007-09-10astro-ph

行星状星云中心恒星奇异的光谱变化

The Bizarre Spectral Variability of Central Stars of Planetary Nebulae

Orsola De Marco, S. Wortel, Howard E. Bond, Dianne Harmer

备注：: 7 pages, 3 figures. To appear in the proceedings of the conference "Asymmetric Planetary Nebulae IV"

摘要：

2002年至2004年期间进行了一次径向速度巡天，以探测双星系统中的中心星。De Marco等人（2004年）报告说，11颗受监测的恒星中有10颗表现出强烈的RV变化，但没有检测到周期。由于其他机制，如风的变化，可以导致明显的RV变化，我们监测了4的10个RV-变星中阶梯分辨率，以确定变异的起源。虽然所有四颗恒星的RV变化都得到了确认，但此时没有一颗恒星可以归因于双星。然而，只有对于IC 4593，风变率才能解释大多数（尽管不是全部）光谱变率。对于BD+332642，无风和无脉动似乎是RV变化的起源。最后，M1-77和M2-54，都是已知的不规则光度变量，表现出显着的RV和线的形状变化的氢和HeI吸收线，以及大RV变化的较弱的线，不改变形状。对于这种变化没有令人满意的解释，尽管风的变化和脉动的组合仍然是使这些恒星如此变化的最佳猜测。我们认为，明亮的中心恒星不适合检测光谱双星，因为风（可能脉动）是无处不在的，甚至会掩盖强周期性。它很可能是一个本质上暗淡的中心恒星的样本将更容易产生二进制信息。

英文摘要：

A radial velocity (RV) survey to detect central stars in binary systems was carried out between 2002 and 2004. De Marco et al. (2004) reported that 10 out of 11 monitored stars exhibited strong RV variability, but periods were not detected. Since other mechanisms, such as wind variability, can cause apparent RV variations, we monitored 4 of the 10 RV-variable stars at echelle resolutions to determine the origin of the variability. Although RV changes are confirmed for all four stars, none of them can be ascribed to binarity at this time. However, only for IC4593 is wind variability able to explain most (though not all) spectral variability. For BD+332642, no wind and no pulsations appear to be the origin of the RV changes. Finally, M1-77 and M2-54, both known to be irregular photometric variables, exhibit dramatic RV and line shape variability of the hydrogen and HeI absorption lines, as well as large RV variability of weaker lines, which do not change in shape. There is no satisfactory explanation of this variability, though a combination of wind variability and pulsations is still the best guess at what makes these stars so variable. We suggest that luminous central stars are ill suited to detect spectroscopic binaries, because winds (and possibly pulsations) are pervasive and would mask even strong periodicities. It it likely that a sample of intrinsically faint central stars would more readily yield binary information.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

摘要：

英文摘要：

相关论文