Speckle Imaging Characterization of Radial Velocity Exoplanet Systems
Speckle Imaging Characterization of Radial Velocity Exoplanet Systems
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DOI：
10.3847/1538-3881/abd6ed
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发表时间：
2020-12
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通讯作者：
P. Dalba;S. Kane;S. Howell;E. Horch;Zhexing Li;L. Hirsch;J. Burt;Timothy D. Brandt;T. Močnik-T.-Moč
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作者：
P. Dalba;S. Kane;S. Howell;E. Horch;Zhexing Li;L. Hirsch;J. Burt;Timothy D. Brandt;T. Močnik-T.-Moč
我们对 53 个恒星系统进行了散斑成像观测，这些恒星系统是长期径向速度 (RV) 监测活动的成员，并表现出明显的加速度，表明宽轨道上有行星或恒星伴星。我们使用双子座南座的差分散斑勘测仪器和 WIYN 望远镜的 NN-Explore 系外行星恒星散斑成像仪，通过蓝色和红色滤光片进行观测。散斑成像识别出主恒星 2 英寸范围内的八个发光伴星。在其中的三个系统（HD 1388、HD 87359 和 HD 104304）中，成像伴星的属性与 RV 测量结果一致，表明这些伴星可能与 RV 变化的主要因素和原因有关。对于所有 53 个恒星系统，我们从成像中得出差分星等限制（即对比曲线）。我们扩展了这种分析，以包括没有成像检测的系统中伴星质量的上限。在 25 个系统中，我们排除了质量大于 0.2 M ⊙ 的伴星，这表明观测到的 RV 信号是由晚 M 矮星或恒星（可能是行星）物体引起的。另一方面，联合 RV 和成像分析几乎完全排除了 HD 19522 RV 信号的行星解释，并表明伴星的角距必须低于零点几角秒。这项工作强调了结合 RV 和成像观测对于表征附近行星系统外部区域的重要性。
We conducted speckle imaging observations of 53 stellar systems that were members of long-term radial velocity (RV) monitoring campaigns and exhibited substantial accelerations indicative of planetary or stellar companions in wide orbits. Our observations were made with blue and red filters using the Differential Speckle Survey Instrument at Gemini-South and the NN-Explore Exoplanet Stellar Speckle Imager at the WIYN telescope. The speckle imaging identifies eight luminous companions within 2″ of the primary stars. In three of these systems—HD 1388, HD 87359, and HD 104304—the properties of the imaged companion are consistent with the RV measurements, suggesting that these companions may be associated with the primary and the cause of the RV variation. For all 53 stellar systems, we derive differential magnitude limits (i.e., contrast curves) from the imaging. We extend this analysis to include upper limits on companion mass in systems without imaging detections. In 25 systems, we rule out companions with masses greater than 0.2 M ⊙, suggesting that the observed RV signals are caused by late-M dwarfs or substellar (potentially planetary) objects. On the other hand, the joint RV and imaging analysis almost entirely rules out planetary explanations of the RV signal for HD 19522 and suggests that the companion must have an angular separation below a few tenths of an arcsecond. This work highlights the importance of combined RV and imaging observations for characterizing the outer regions of nearby planetary systems.