Simulating the Multi-epoch Direct Detection Technique to Isolate the Thermal Emission of the Non-transiting Hot Jupiter HD187123b
Simulating the Multi-epoch Direct Detection Technique to Isolate the Thermal Emission of the Non-transiting Hot Jupiter HD187123b
复制标题
模拟多历元直接探测技术隔离非凌日热木星HD187123b的热发射
作者：
C. Buzard;L. Finnerty;D. Piskorz;S. Pelletier;B. Benneke;C. Bender;A. Lockwood;N. Wallack;O. Wilkins;G. Blake
我们报告了从开普勒轨道速度 Kp 为 53 ± 13 km s−1 的热木星 HD187123b 中检测到的水的 6.5σ 值。这种高置信度探测是使用多历元、高分辨率、互相关技术进行的，对应于 MJ 的行星质量和 21° ± 5° 的轨道倾角。该技术的工作原理是将行星/恒星系统视为光谱双星，并在行星轨道上的多个点获得高信噪比、高分辨率的观测结果，以约束系统的双星动态运动。总共获得了 7 个 Keck/NIRSPEC L 波段观测结果，其中 5 个在仪器升级之前，2 个在仪器升级之后。使用高分辨率 SCARLET 行星和 PHOENIX 恒星光谱模型，我们能够通过运行模拟来显着提高检测的置信度，这些模拟可以重现并消除最终似然空间中的非随机结构噪声。预测多时期结果的能力对于进一步发展该技术将非常有用。在这里，我们使用这些模拟来比较三种不同的方法来组合高分辨率光谱的互相关性，并发现 Zucker log(L) 方法受我们的 HD187123 数据集的不需要的行星/恒星相关性的影响最小。此外，我们发现相同的总信噪比 (S/N) 在许多较低 S/N 历元中分布在轨道上，而不是在较少的较高 S/N 历元中，可以提供更有效的检测。这项工作为多历元模拟提供了必要的验证，可用于指导未来的观测，并将成为研究相距较远、非凌日系外行星大气层的关键。
We report the 6.5σ detection of water from the hot Jupiter HD187123b with a Keplerian orbital velocity Kp of 53 ± 13 km s−1. This high-confidence detection is made using a multi-epoch, high-resolution, cross-correlation technique, and corresponds to a planetary mass of MJ and an orbital inclination of 21° ± 5°. The technique works by treating the planet/star system as a spectroscopic binary and obtaining high signal-to-noise, high-resolution observations at multiple points across the planet’s orbit to constrain the system’s binary dynamical motion. All together, seven epochs of Keck/NIRSPEC L-band observations were obtained, with five before the instrument upgrade and two after. Using high-resolution SCARLET planetary and PHOENIX stellar spectral models, we were able to drastically increase the confidence of the detection by running simulations that could reproduce, and thus remove, the nonrandom structured noise in the final likelihood space well. The ability to predict multi-epoch results will be extremely useful for furthering the technique. Here, we use these simulations to compare three different approaches to combining the cross correlations of high-resolution spectra and find that the Zucker log(L) approach is least affected by unwanted planet/star correlation for our HD187123 data set. Furthermore, we find that the same total signal-to-noise ratio (S/N) spread across an orbit in many, lower S/N epochs rather than fewer, higher S/N epochs could provide a more efficient detection. This work provides a necessary validation of multi-epoch simulations, which can be used to guide future observations and will be key to studying the atmospheres of farther separated, non-transiting exoplanets.
RadVel：径向速度建模工具包
DOI：
10.1088/1538-3873/aaaaa8
发表时间：
2018
影响因子：
3.5
作者：
Fulton, Benjamin J.;Petigura, Erik A.;Blunt, Sarah;Sinukoff, Evan
通讯作者：
Sinukoff, Evan