Spitzer Transit Follow-up of Planet Candidates from the K2 Mission
Spitzer Transit Follow-up of Planet Candidates from the K2 Mission
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DOI：
10.3847/1538-3881/aaff69
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发表时间：
2019-01
期刊：
影响因子：
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通讯作者：
J. Livingston;I. Crossfield;M. Werner;V. Gorjian;E. Petigura;D. Ciardi;C. Dressing;B. Fulton
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文献类型：
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作者：
J. Livingston;I. Crossfield;M. Werner;V. Gorjian;E. Petigura;D. Ciardi;C. Dressing;B. Fulton
我们对K2任务发现的8颗候选行星进行了精确的4.5斯皮策凌日光度测量：K2-52 b、K2-53 b、EPIC 205084841.01、K2-289 b、K2-174 b、K2-87 b、K2-90 b和K2-124 b。样本包括4颗亚海王星和2颗亚土星，半径在2.6到18之间，平衡温度在440到2000 K之间。在本文中，我们确定了未来表征研究的几个潜在兴趣目标，展示了凌日后续观测对行星验证和星历表改进的效用，并提供了新的成像和光谱数据。我们对K2和斯皮策光曲线的同时分析，提高了对行星半径和多波长信息的估计，有助于验证它们的行星性质，包括之前未经验证的候选EPIC 205686202.01 （K2-289 b）。我们的斯皮策观测结果使星历表精度提高了一个数量级，从而通过将2021年中期典型的凌日时间不确定性从几个小时减少到十几分钟左右，为未来有效研究这些有趣的系统铺平了道路。考虑到目前可用或正在开发的光谱仪的性能，K2-53 b、K2-289 b、K2-174 b、K2-87 b和K2-90 b是很有希望的径向速度（RV）目标，M3V恒星K2-124拥有一颗温带的海王星，可能是RV和大气表征研究的一个很好的目标。
We present precision 4.5 Spitzer transit photometry of eight planet candidates discovered by the K2 mission: K2-52 b, K2-53 b, EPIC 205084841.01, K2-289 b, K2-174 b, K2-87 b, K2-90 b, and K2-124 b. The sample includes four sub-Neptunes and two sub-Saturns, with radii between 2.6 and 18 and equilibrium temperatures between 440 and 2000 K. In this paper we identify several targets of potential interest for future characterization studies, demonstrate the utility of transit follow-up observations for planet validation and ephemeris refinement, and present new imaging and spectroscopy data. Our simultaneous analysis of the K2 and Spitzer light curves yields improved estimates of the planet radii and multiwavelength information that helps validate their planetary nature, including the previously unvalidated candidate EPIC 205686202.01 (K2-289 b). Our Spitzer observations yield an order-of-magnitude increase in ephemeris precision, thus paving the way for efficient future study of these interesting systems by reducing the typical transit timing uncertainty in mid-2021 from several hours to a dozen or so minutes. K2-53 b, K2-289 b, K2-174 b, K2-87 b, and K2-90 b are promising radial velocity (RV) targets given the performance of spectrographs available today or in development, and the M3V star K2-124 hosts a temperate sub-Neptune that is potentially a good target for both RV and atmospheric characterization studies.