Asteroseismological Observations of the Central Star of the Planetary Nebula NGC 1501
Asteroseismological Observations of the Central Star of the Planetary Nebula NGC 1501
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DOI：
10.1086/118214
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发表时间：
1996-09
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通讯作者：
H. Bond;S. Kawaler;R. Ciardullo;R. Stover;T. Kuroda;T. Ishida;T. Ono;S. Tamura;H. Malasan;A. Yamasaki;O. Hashimoto;E. Kambe;M. Takeuti;T. Kato;M. Kato;J.-S. Chen;E. Leibowitz;M. Roth;T. Soffner;W.Mitsch
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作者：
H. Bond;S. Kawaler;R. Ciardullo;R. Stover;T. Kuroda;T. Ishida;T. Ono;S. Tamura;H. Malasan;A. Yamasaki;O. Hashimoto;E. Kambe;M. Takeuti;T. Kato;M. Kato;J.-S. Chen;E. Leibowitz;M. Roth;T. Soffner;W.Mitsch
我们报告了一项全球CCD时间序列光度测量运动，以解码行星状星云NGC1501的核心脉动。这颗恒星温度高且缺乏氢，类似于前白矮星PG 1159。NGC1501显示出几个百分点的脉动亮度变化，周期从19分钟到87分钟不等。这些变化非常复杂，表明脉动谱需要很长的不间断时间序列来解决。1991年11月，我们利用全球观测站网络对这颗恒星进行了为期两周的CCD光度测量。在测试过程中，我们在一周的间隔内获得了几乎连续的覆盖。我们已经确定了10个脉动周期，范围从5235秒到1154秒。我们发现有力的证据表明，模态确实是非径向g模态。最大振幅模态的频率比与那些由于外层密度不连续而被捕获的模态的频率比一致。我们提供了一个脉动谱模型，该模型包括22.3 s的共同周期间隔和1.17天的自转周期；周期间隔使我们能够确定地震质量为0.55+/-0.03 Msun。
We report on a global CCD time-series photometric campaign to decode the pulsations of the nucleus of the planetary nebula NGC1501. The star is hot and hydrogen-deficient, similar to the pre-white-dwarf PG 1159 stars. NGC1501 shows pulsational brightness variations of a few percent with periods ranging from 19 to 87 minutes. The variations are very complex, suggesting a pulsation spectrum that requires a long unbroken time series to resolve. Our CCD photometry of the star covers a two-week period in 1991 November, and used a global network of observatories. We obtained nearly continuous coverage over an interval of one week in the middle of the run. We have identified 10 pulsation periods, ranging from 5235 s down to 1154 s. We find strong evidence that the modes are indeed nonradial g-modes. The ratios of the frequencies of the largest-amplitude modes agree with those expected for modes that are trapped by a density discontinuity in the outer layers. We offer a model for the pulsation spectrum that includes a common period spacing of 22.3 s and a rotation period of 1.17 days; the period spacing allows us to assign a seismological mass of 0.55+/-0.03 Msun.