A Stellar Activity F-statistic for Exoplanet Surveys (SAFE)
A Stellar Activity F-statistic for Exoplanet Surveys (SAFE)
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DOI：
10.3847/1538-3881/abf5e0
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发表时间：
2021-04
期刊：
影响因子：
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通讯作者：
Parker H. Holzer;J. Cisewski-Kehe;Lily L. Zhao;E. Ford;C. Gilbertson;D. Fischer
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作者：
Parker H. Holzer;J. Cisewski-Kehe;Lily L. Zhao;E. Ford;C. Gilbertson;D. Fischer
在寻找绕遥远恒星运行的行星时，被观测恒星大气中恒星活动的存在可能会掩盖用于探测此类行星的径向速度信号。此外，这种恒星活动污染是由恒星本身造成的，不能简单地通过更好的仪器来避免。已经开发出各种可能与这种污染相关的恒星活动指标。我们引入了一种新的恒星活动指标，称为系外行星巡天恒星活动 F 统计量 (SAFE)，在对具有中等到高信噪比的类太阳恒星活动区域的模拟研究中，它比许多传统的恒星活动指标具有更高的统计功效（即检测到真实恒星活动信号的概率）。此外，通过模拟，SAFE 被证明与活跃区域覆盖的恒星可见侧的投影面积相关。我们还证明，SAFE 在 HD 22049 的大部分光谱中检测到统计上显着的恒星活动，HD 22049 是一颗已知具有高恒星变异性的恒星。此外，SAFE 是针对最近对三颗低变性恒星 HD 34411、HD 10700 和 HD 3651 的观测而计算的，已知后者有一个行星伴星。正如预期的那样，SAFE 仅偶尔检测到这三个活动。此外，初步探索似乎表明 SAFE 可能有助于从行星引起的多普勒频移中解开恒星活动信号。
In the search for planets orbiting distant stars, the presence of stellar activity in the atmospheres of observed stars can obscure the radial velocity signal used to detect such planets. Furthermore, this stellar activity contamination is set by the star itself and cannot simply be avoided with better instrumentation. Various stellar activity indicators have been developed that may correlate with this contamination. We introduce a new stellar activity indicator called the Stellar Activity F-statistic for Exoplanet surveys (SAFE) that has higher statistical power (i.e., probability of detecting a true stellar activity signal) than many traditional stellar activity indicators in a simulation study of an active region on a Sun-like star with a moderate-to-high signal-to-noise ratio. Also through simulation, the SAFE is demonstrated to be associated with the projected area on the visible side of the star covered by active regions. We also demonstrate that the SAFE detects statistically significant stellar activity in most of the spectra for HD 22049, a star known to have high stellar variability. Additionally, the SAFE is calculated for recent observations of the three low-variability stars HD 34411, HD 10700, and HD 3651, the latter of which is known to have a planetary companion. As expected, the SAFE for these three only occasionally detects activity. Furthermore, initial exploration appears to indicate that the SAFE may be useful for disentangling stellar activity signals from planet-induced Doppler shifts.