论文标题
嘉年华二世。从傅立叶域中的外球星多普勒偏移中解开恒星和仪器变异性
FIESTA II. Disentangling stellar and instrumental variability from exoplanetary Doppler shifts in Fourier domain
论文作者
论文摘要
出色的光谱变异性挑战了外部球星的径向速度（RV）检测，可以模仿行星的存在和工具不稳定性，从而进一步掩盖了检测。恒星和仪器变化都会扭曲光谱线轮廓，并被误解为明显的RV偏移。 我们提出了一个改进的傅立叶\ textit {stape}频谱分析（Fiesta a.K.A. $ \ Mathitϕ $ esta），以从真实的多普勒移位线变形，从而将明显的速度变化驱动。 $ \ Mathitϕ $ ESTA Project Stellar Spectrum的互相关函数（CCF）在截断的傅立叶基函数集上。使用来自每个傅立叶模式的振幅和相位信息，我们可以在不同的CCF宽度尺度上追踪线变异性，以稳健地识别和减轻多种RV污染源。例如，在我们对3年竖琴-N太阳能数据的研究中，$ \ Mathit ϕ $ ESTA揭示了太阳旋转效应，太阳能磁性周期，工具不稳定性和明显的太阳旋转速率变化引起的长期趋势。在$ \ Mathit ϕ $ esta指标上应用多个线性回归模型，我们将加权RMS噪声从1.89 m/s降低到0.98 m/s。此外，我们观察到$ \ sim $ 3天的滞后在$ \ mathit ϕ $ esta指标中，类似于先前对BIS和FWHM的研究结果。
The radial velocity (RV) detection of exoplanets is challenged by stellar spectroscopic variability that can mimic the presence of planets and by instrumental instability that can further obscure the detection. Both stellar and instrumental changes can distort the spectral line profiles and be misinterpreted as apparent RV shifts. We present an improved FourIEr \textit{phase} SpecTrum Analysis (FIESTA a.k.a. $\mathitϕ$ESTA) to disentangle apparent velocity shifts due to a line deformation from a true Doppler shift. $\mathitϕ$ESTA projects stellar spectrum's cross correlation function (CCF) onto a truncated set of Fourier basis functions. Using the amplitude and phase information from each Fourier mode, we can trace the line variability at different CCF width scales to robustly identify and mitigate multiple sources of RV contamination. For example, in our study of the 3 years of HARPS-N solar data, $\mathitϕ$ESTA reveals the solar rotational effect, the long-term trend due to solar magnetic cycle, instrumental instability and apparent solar rotation rate changes. Applying a multiple linear regression model on $\mathitϕ$ESTA metrics, we reduce the weighted rms noise from 1.89 m/s to 0.98 m/s. In addition, we observe a $\sim$3 days lag in the $\mathitϕ$ESTA metrics, similar to the findings from previous studies on BIS and FWHM.
