Asteroseismology of the PG 1159 star PG 0122+200
Asteroseismology of the PG 1159 star PG 0122+200
复制标题
PG 1159 星 PG 0122 200 的星震学
DOI：
10.1051/0004-6361:20066295
复制
发表时间：
2007-05
影响因子：
6.5
通讯作者：
Park, B.-G.
中科院分区：
文献类型：
--
作者：
Chevreton, M.;Taguchi, H.;Leibowitz, E.;O'Brien, M.S.;Dreizler, S.;Medupe, R.;Kinugasa, K.;Gonzalez Perez, J.;H;ler, G.;Dolez, N.;Schuh, S.;Fu, J.-N.;Solheim, J.-E.;Kim, S.-L.;Vauclair, G.;Hashimoto, O.;Provencal, J.;Kambe, E.;Wood, M.;Park, B.-G.
上下文。可变前白矮星PG 1159恒星（GW Vir）是g模非径向脉冲星。星震学对它们的全局参数和内部结构有很强的限制。PG 0122+200定义了不稳定带的红边，其演化时间尺度预计由中微子发射主导。它的研究为更好地理解不稳定性机制和验证致密等离子体中中微子产生的物理学提供了机会。目标。要实现这一目标，需要精确地确定其基本参数。这就是本文的目标。方法。我们介绍了2001年和2002年获得的新的多站点光度观测结果。结合之前的数据，我们可以检测到23个频率，由7个三重频率和2个单频率组成，用于约束其内部结构并推导其基本参数。结果。所有观测到的频率都对应于- = 1 g模态。周期分布表现出模式俘获特征，据此我们约束富氦包络质量分数为-6.0≤log(qy)≤- 5.3。GW - Vir恒星的模捕获幅度的比较表明，当Teff≤140 kK时，质量损失效率将显著降低。我们测量到的平均周期间隔为22.9 s，由此得出的质量为0.59±0.02 μ M。从三胞胎中，我们测量到平均旋转分裂为3.74 μ Hz，旋转周期为1.55天。我们推导出B≤4 × 10 3 g的磁场上限，光度（logL/L = 1.3±0.5）和距离（D = 0.7 +1.0−0.4 kpc）仅受到微弱的约束，这是由于光谱推导出的表面重力存在很大的不确定性和没有测量到的视差。结论。从星震质量来看，微中子光度与光子光度之比为1.6±0.2，证实PG 0122+200演化时间尺度应以微中子冷却为主。对最大振幅未捕获模式的u P测量应该验证这一预测。
Context. The variable pre-white dwarf PG 1159 stars (GW Vir) are g-mode non-radial pulsators. Asteroseismology puts strong constraints on their global parameters and internal structure. PG 0122+200 defines the red edge of the instability strip and its evolutionary timescale is predicted to be dominated by neutrino emission. Its study offers the opportunity to better understand the instability mechanism and to validate the physics of the neutrino production in dense plasma. Aims. To achieve such a goal requires determining precisely its fundamental parameters. This is the goal of this paper. Methods. We present new multi-site photometric observations obtained in 2001 and 2002. Together with previous data, they allow us to detect 23 frequencies, composed of 7 triplets and 2 single frequencies, which are used to constrain its internal structure and derive its fundamental parameters. Results. All the observed frequencies correspond to � = 1 g-modes. The period distribution shows a signature of mode trapping from which we constrain the He-rich envelope mass fraction to be –6.0 ≤ log(qy) ≤− 5.3. The comparison of the mode trapping amplitudes among GW Vir stars suggests that the mass-loss efficiency must decrease significantly below Teff ≤ 140 kK. We measure an average period spacing of 22.9 s from which we derive a mass of 0.59 ± 0.02 M� . From the triplets we measure a mean rotational splitting of 3.74 µHz and a rotational period of 1.55 days. We derive an upper limit to the magnetic field of B ≤ 4 × 10 3 G. The luminosity (logL/L� = 1.3 ± 0.5) and the distance (D = 0.7 +1.0 −0.4 kpc) are only weakly constrained due to the large uncertainty on the spectroscopically derived surface gravity and the absence of a measured parallax. Conclusions. From the asteroseismic mass, the ratio of the neutrino luminosity on the photon luminosity is 1.6 ± 0.2 confirming that the PG 0122+200 evolutionary time scale should be dominated by neutrino cooling. A measurement of u P for the largest amplitude untrapped modes should verify this prediction.
登录
查看更多内容
DOI：
10.1086/309216
发表时间：
2000-03
期刊：
The Astrophysical Journal
影响因子：
--
作者：
M. O'Brien;S. Kawaler
通讯作者：
M. O'Brien;S. Kawaler
影响因子：
3.5
作者：
P. Bergeron;F. Wesemael;A. Beauchamp
通讯作者：
P. Bergeron;F. Wesemael;A. Beauchamp
DOI：
10.1086/169196
发表时间：
1990-09
期刊：
The Astrophysical Journal
影响因子：
--
作者：
R. Nather;D. Winget;J. Clemens;C. Hansen;B. Hine
通讯作者：
R. Nather;D. Winget;J. Clemens;C. Hansen;B. Hine
影响因子：
6.5
作者：
A. C'orsico;L. Althaus;M. M. Bertolami-M.;K. Werner
通讯作者：
A. C'orsico;L. Althaus;M. M. Bertolami-M.;K. Werner
DOI：
10.1086/170434
发表时间：
1991-09
期刊：
--
影响因子：
--
作者：
D. Winget;D. Winget;R. Nather;J. Clemens;J. Provencal;S. Kleinman;P. Bradley;M. Wood;C. Claver;M. Frueh;A. Grauer;B. Hine;C. Hansen;G. Fontaine;N. Achilleos;D. Wickramasinghe;T. Marar;S. Seetha;B. N. Ashoka;D. O'donoghue;B. Warner;D. Kurtz;D. Buckley;J. Brickhill;G. Vauclair;N. Dolez;M. Chevreton;M. Barstow;J. Solheim;A. Kanaan;S. O. Kepler;G. Henry;S. Kawaler
通讯作者：
D. Winget;D. Winget;R. Nather;J. Clemens;J. Provencal;S. Kleinman;P. Bradley;M. Wood;C. Claver;M. Frueh;A. Grauer;B. Hine;C. Hansen;G. Fontaine;N. Achilleos;D. Wickramasinghe;T. Marar;S. Seetha;B. N. Ashoka;D. O'donoghue;B. Warner;D. Kurtz;D. Buckley;J. Brickhill;G. Vauclair;N. Dolez;M. Chevreton;M. Barstow;J. Solheim;A. Kanaan;S. O. Kepler;G. Henry;S. Kawaler