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arXiv 1004.4891astro-ph.SR
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类太阳CoRoT目标HD 170987:光谱和地震观测

The solar-like CoRoT target HD 170987: spectroscopic and seismic observations

S. Mathur, R. A. Garcia, C. Catala, H. Bruntt, B. Mosser, T. Appourchaux, J. Ballot, O. L. Creevey, P. Gaulme, S. Hekker, D. Huber, C. Karoff, L. Piau, C. Regul… 展开作者

S. Mathur, R. A. Garcia, C. Catala, H. Bruntt, B. Mosser, T. Appourchaux, J. Ballot, O. L. Creevey, P. Gaulme, S. Hekker, D. Huber, C. Karoff, L. Piau, C. Regulo, I. W. Roxburgh, D. Salabert, G. A. Verner, M. Auvergne, A. Baglin, W. J. Chaplin, Y. Elsworth, E. Michel, R. Samadi, K. H Sato, D. Stello

摘要:

CoRoT飞行任务已进入第三个观测年,目前正在分析银河系中心方向第二次长期运行的数据。到目前为止,已经观测到的类太阳振荡星已经给出了一些有趣的结果,特别是关于振幅低于预测的结果。本文给出了对HD 170987恒星的分析结果,目的是确定HD 170987的全局参数。我们寻找全球地震参数,如平均大分离,最大振幅的模式,和表面旋转,因为观测中的信噪比不允许我们测量个别模式。我们还希望检索恒星的恒星参数和它的化学成分。我们已经研究了恒星的化学成分,使用地面观测与NARVAL摄谱仪进行。我们已经使用了几种方法来计算全球参数的声学振荡的基础上CoRoT数据。恒星的光变曲线已经使用修复算法进行了插值,以减少数据间隙的影响。我们发现在[400 - 1200] μ Hz范围内与p模相关的功率过剩,平均大分离度为55.2 ± 0.8 μ Hz,概率大于95%,在更高的频率范围[500 - 1250] μ Hz和1%的抑制水平下增加到55.9 ± 0.2 μ Hz。这颗恒星的自转周期约为4.3天,倾角轴为i=50 deg +20/-13。我们测量的辐射热振幅每径向模式在范围[2.4 - 2.9] ppm约1000 μ Hz。最后,利用网格模型,我们估计出恒星质量M=1.43+-0.05 Msun,半径R=1.96+-0.046 Rsun,年龄~2.4 Gyr。

英文摘要:

The CoRoT mission is in its third year of observation and the data from the second long run in the galactic centre direction are being analysed. The solar-like oscillating stars that have been observed up to now have given some interesting results, specially concerning the amplitudes that are lower than predicted. We present here the results from the analysis of the star HD 170987.The goal of this research work is to characterise the global parameters of HD 170987. We look for global seismic parameters such as the mean large separation, maximum amplitude of the modes, and surface rotation because the signal-to-noise ratio in the observations do not allow us to measure individual modes. We also want to retrieve the stellar parameters of the star and its chemical composition.We have studied the chemical composition of the star using ground-based observations performed with the NARVAL spectrograph. We have used several methods to calculate the global parameters from the acoustic oscillations based on CoRoT data. The light curve of the star has been interpolated using inpainting algorithms to reduce the effect of data gaps. We find power excess related to p modes in the range [400 - 1200]muHz with a mean large separation of 55.2+-0.8muHz with a probability above 95% that increases to 55.9 +-0.2muHz in a higher frequency range [500 - 1250] muHz and a rejection level of 1%. A hint of the variation of this quantity with frequency is also found. The rotation period of the star is estimated to be around 4.3 days with an inclination axis of i=50 deg +20/-13. We measure a bolometric amplitude per radial mode in a range [2.4 - 2.9] ppm around 1000 muHz. Finally, using a grid of models, we estimate the stellar mass, M=1.43+-0.05 Msun, the radius, R=1.96+-0.046 Rsun, and the age ~2.4 Gyr.

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。

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