A multi-site campaign to measure solar-like oscillations in Procyon. II. Mode frequencies
T. R. Bedding, H. Kjeldsen, T. L. Campante, T. Appourchaux, A. Bonanno, W. J. Chaplin, R. A. Garcia, M. Martic, B. Mosser, R. P. Butler, H. Bruntt, L. L. Kiss, … 展开作者
T. R. Bedding, H. Kjeldsen, T. L. Campante, T. Appourchaux, A. Bonanno, W. J. Chaplin, R. A. Garcia, M. Martic, B. Mosser, R. P. Butler, H. Bruntt, L. L. Kiss, S. J. O'Toole, E. Kambe, H. Ando, H. Izumiura, B. Sato, M. Hartmann, A. Hatzes, C. Barban, G. Berthomieu, E. Michel, J. Provost, S. Turck-Chieze, J. -C. Lebrun, J. Schmitt, J. -L. Bertaux, S. Benatti, R. U. Claudi, R. Cosentino, S. Leccia, S. Frandsen, K. Brogaard, L. Glowienka, F. Grundahl, E. Stempels, T. Arentoft, M. Bazot, J. Christensen-Dalsgaard, T. H. Dall, C. Karoff, J. Lundgreen-Nielsen, F. Carrier, P. Eggenberger, D. Sosnowska, R. A. Wittenmyer, M. Endl, T. S. Metcalfe, S. Hekker, S. Reffert
We have analyzed data from a multi-site campaign to observe oscillations in the F5 star Procyon. The data consist of high-precision velocities that we obtained over more than three weeks with eleven telescopes. A new method for adjusting the data weights allows us to suppress the sidelobes in the power spectrum. Stacking the power spectrum in a so-called echelle diagram reveals two clear ridges that we identify with even and odd values of the angular degree (l=0 and 2, and l=1 and 3, respectively). We interpret a strong, narrow peak at 446 muHz that lies close to the l=1 ridge as a mode with mixed character. We show that the frequencies of the ridge centroids and their separations are useful diagnostics for asteroseismology. In particular, variations in the large separation appear to indicate a glitch in the sound-speed profile at an acoustic depth of about 1000 s. We list frequencies for 55 modes extracted from the data spanning 20 radial orders, a range comparable to the best solar data, which will provide valuable constraints for theoretical models. A preliminary comparison with published models shows that the offset between observed and calculated frequencies for the radial modes is very different for Procyon than for the Sun and other cool stars. We find the mean lifetime of the modes in Procyon to be 1.29 +0.55/-0.49 days, which is significantly shorter than the 2-4 days seen in the Sun.
Photometry and spectroscopy of massive stars observed during K2 Campaign 8
我们在本文中报告了2016年1月至3月开普勒/K2任务第8阶段观测到的8颗大质量恒星的光谱和光度分析。在巴西的OPD/LNA获得了这些恒星的光谱数据，并使用SME确定了它们的恒星参数。通过CLEANEST和PERIOD 04算法进行光变曲线的定期分析。我们的恒星的质量，光度和半径是使用CESAM+POSC网格估计的。我们的三颗恒星显示出明显的周期性。K2 ID 220679442和K2 ID 220532854的周期与恒星自转有关。K2 ID 220532854有着显著的硅线（Si II 4128-4131），这是一种特殊的Ap型主序星。然而，在我们的光谱分析中，这个物体被发现是一颗进化的发光巨星。K2 ID 220466722被发现是一颗盾牌座$δ$变星，并有40个独立的频率被确定。在这项工作中分析的其余恒星的光变曲线中没有发现明显的周期性，除了仪器的。
Short-term spectroscopic variability of Plaskett's star
上下文普拉斯凯特的恒星（HD 47129）是一颗质量非常大的O型双星，处于后罗奇瓣溢出阶段。该系统的CoRoT观测揭示了光度的变化与一些频率。目标。本文的目的是表征光谱的变化，并调查其起源。方法.为了对HD 47129的短期变异性进行采样，在两次光谱活动中对它进行了密集监测，每次六个晚上。光谱被解开和傅立叶分析进行，以确定可能的周期性和研究的相位常数和振幅的周期性的波长依赖性。结果观察到复杂的线轮廓变化。在He i 4471、He ii 4542和N iii 4510-4518谱线中始终检测到接近1.65、0.82和0.37 d^-1的频率。这些频率与测光中检测到的最强信号的频率一致。这些变化源于脉动，最近检测到的磁场或潮汐相互作用的可能性进行了讨论。结论.虽然所有三种情况都有其优势，但目前没有一种情况可以解释所有观测到的线路轮廓变化特性。
Investigating magnetic activity cycles in solar-like oscillators using asteroseismic data from the K2 mission
University of Warwick（华威大学）；Centre for Fusion, Space and Astrophysics, University of Warwick（华威大学聚变、空间与天体物理中心）；School of Physics and Astronomy, University of Birmingham（伯明翰大学物理与天文学院）；Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University（奥胡斯大学物理与天文学院恒星天体物理中心）；Engineering Research Institute “Ventspils International Radio Astronomy Centre (VIRAC)”, Ventspils University of Applied Sciences（文茨皮尔斯应用科学大学文茨皮尔斯国际射电天文中心（VIRAC）工程研究所）
A Coordinated X-ray and Optical Campaign of the Nearest Massive Eclipsing Binary, delta Orionis Aa: III. Analysis of Optical Photometric MOST and Spectroscopic (Ground Based) Variations
我们报告了来自MOST空间望远镜的高精度测光和三重系统delta Ori A的地基光谱学，该系统由P = 5.7d的二进制O9.5II+早期B（Aa1和Aa2）和更遥远的第三（O9 IV P > 400 yrs）组成。这些数据是与钱德拉X射线天文台的X射线光谱学一起收集的。由于连续3周的覆盖，MOST光变曲线首次在非相位数据中揭示了Aa1和Aa2之间的清晰日食。根据光谱，我们有一个很好的约束径向速度曲线Aa1。虽然我们无法恢复径向速度的变化的二级恒星，我们能够约束这个系统的几个基本参数，并确定一个近似的质量使用拱点运动的主要。我们还检测到二阶调制在12个独立的频率与间距潮汐影响的振荡指示。这些间距从未在大质量双星中看到过，使该系统成为少数几个显示潮汐诱导脉动证据的双星之一。
