Stellar activity analysis of Barnard’s Star: Very slow rotation and evidence for long-term activity cycle
Stellar activity analysis of Barnard’s Star: Very slow rotation and evidence for long-term activity cycle
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巴纳德星的恒星活动分析：极慢的自转和长期活动周期的证据
DOI：
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发表时间：
2018
影响因子：
4.8
通讯作者：
S. Vanaverbeke
中科院分区：
文献类型：
--
作者：
B. Toledo;J. Hern'andez;C. Rodr'iguez;A. Mascareno;R. Rebolo;R. P. Butler;I. Ribas;G. Anglada;E. Johnson;A. Reiners;J. Caballero;A. Quirrenbach;P. Amado;V. B'ejar;J. Morales;M. Perger;S. Jeffers;S. Vogt;J. Teske;S. Shectman;J. Crane;M. D'iaz;P. Arriagada;B. Holden;J. Burt;E. Rodr'iguez;E. Herrero;F. Murgas;E. Pall'e;N. Morales;M. J. L'opez;E. D. Alonso;M. Tuomi;M. Kiraga;S. Engle;E. Guinan;J. Strachan;F. Aceituno;J. Aceituno;V. Casanova;S. Mart'in;D. Montes;J. Ortiz;A. Sota;J. Briol;L. Barbieri;I. Cervini;M. Deldem;F. Dubois;F. Hambsch;B. Harris;C. Kotnik;L. Logie;J. López;M. Mcneely;Y. Ogmen;L. P'erez;S. Rau;D. Rodr'iguez;F. S. Urquijo;S. Vanaverbeke
使用超稳定摄谱仪寻找晚型恒星周围的类地行星需要非常精确地描述恒星活动和星星的磁周期，因为这些现象会引起径向速度（RV）信号，这些信号可能被误解为行星信号。在附近的恒星中，我们选择了巴纳德星星（G1 699），使用一组光谱数据来描述这些现象，这些光谱数据覆盖了大约14.5年，来自七个不同的摄谱仪：HARPS，HARPS-N，CARMENES，HIRES，UVES，APF和PFS;以及一组光度数据，覆盖了大约15.1年，来自四个不同的光度来源：ASAS、FCAPT-RCT、AAVSO和SNO。我们测量了不同的色球活动指标（Hα，Ca II HK和Na I D），以及为光谱数据的子集计算的互相关函数的半高宽。对不同活动指标时间序列的广义Lomb-Scargle周期图分析表明，该星星的自转周期为145 ± 15天，与根据该星星低活动水平和之前的说法所预期的自转周期一致。对应于该旋转周期的预测活动诱导RV信号的上限为约lm/s。我们还发现了一个10 ± 2年的长期周期的证据，这与之前从其他类似活动水平的M星的光度时间序列中对磁周期的估计一致。现有的星星光度数据也支持长期和旋转信号的检测。
The search for Earth-like planets around late-type stars using ultra-stable spectrographs requires a very precise characterization of the stellar activity and the magnetic cycle of the star, since these phenomena induce radial velocity (RV) signals that can be misinterpreted as planetary signals. Among the nearby stars, we have selected Barnard’s Star (Gl 699) to carry out a characterization of these phenomena using a set of spectroscopic data that covers about 14.5 years and comes from seven different spectrographs: HARPS, HARPS-N, CARMENES, HIRES, UVES, APF, and PFS; and a set of photometric data that covers about 15.1 years and comes from four different photometric sources: ASAS, FCAPT-RCT, AAVSO, and SNO. We have measured different chromospheric activity indicators (Hα, Ca II HK and Na I D), as well as the FWHM of the cross-correlation function computed for a sub-set of the spectroscopic data. The analysis of Generalized Lomb-Scargle periodograms of the time series of different activity indicators reveals that the rotation period of the star is 145 ± 15 days, consistent with the expected rotation period according to the low activity level of the star and previous claims. The upper limit of the predicted activity-induced RV signal corresponding to this rotation period is about 1 m/s. We also find evidence of a long-term cycle of 10 ± 2 years that is consistent with previous estimates of magnetic cycles from photometric time series in other M stars of similar activity levels. The available photometric data of the star also support the detection of both the long-term and the rotation signals.
轮换与活动关系的广义研究：支持轮换周期而不是罗斯比数
DOI：
10.1088/0004-637x/794/2/144
发表时间：
2014
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Reiners;Schüssler;Passegger
通讯作者：
Passegger