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arXiv 1702.01657astro-ph.EP
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KELT-18 b：膨胀的星球，热主机，可能受到干扰

KELT-18b: Puffy Planet, Hot Host, Probably Perturbed

Kim K. McLeod, Joseph E. Rodriguez, Ryan J. Oelkers, Karen A. Collins, Allyson Bieryla, Benjamin J. Fulton, Keivan G. Stassun, B. Scott Gaudi, Kaloyan Penev, Da… 展开作者

Kim K. McLeod, Joseph E. Rodriguez, Ryan J. Oelkers, Karen A. Collins, Allyson Bieryla, Benjamin J. Fulton, Keivan G. Stassun, B. Scott Gaudi, Kaloyan Penev, Daniel J. Stevens, Knicole D. Colón, Joshua Pepper, Norio Narita, Ryu Tsuguru, Akihiko Fukui, Phillip A. Reed, Bethany Tirrell, Tiffany Visgaitis, John F. Kielkopf, David H. Cohen, Eric L. N. Jensen, Joao Gregorio, Özgür Baştürk, Thomas E. Oberst, Casey Melton, Eliza M. -R. Kempton, Andrew Baldridge, Y. Sunny Zhao, Roberto Zambelli, David W. Latham, Gilbert A. Esquerdo, Perry Berlind, Michael L. Calkins, Andrew W. Howard, Howard Isaacson, Lauren M. Weiss, Thomas G. Beatty, Jason D. Eastman, Matthew T. Penny, Robert J. Siverd, Michael B. Lund, Jonathan Labadie-Bartz, G. Zhou, Ivan A. Curtis, Michael D. Joner, Mark Manner, Howard Relles, Gaetano Scarpetta, Denise C. Stephens, Chris Stockdale, T. G. Tan, D. L. DePoy, Jennifer L. Marshall, Richard W. Pogge, Mark Trueblood, Patricia Trueblood

备注：
16 pages, 13 figures, 6 tables, accepted to AJ
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摘要：

我们报告发现了KELT-18 b，这是一颗在2.87 d轨道上围绕明亮（V=10.1）的热F4 V恒星BD+60 1538（TYC 3865-1173-1）运行的热木星。我们提出了后续的测光，光谱，和自适应光学成像，允许系统的详细表征。我们首选的模型拟合产生的宿主恒星温度为6670+/-120 K，质量为1.524+/-0.069 Msun，将其定位为少数已知的凌日行星之一，其宿主是热的，质量大，明亮。这颗行星的质量为1.18+/-0.11兆焦耳（Mjup），半径为1.57+/-0.04兆焦耳（Rjup），密度为0.377+/-0.040克/立方厘米，使其成为已知围绕热恒星的最膨胀的行星之一。我们认为，KELT-18 b的高温和低表面重力，产生约600公里的大气尺度高度，结合其热，明亮的主机，使其成为一个很好的候选人，旨在观测大气特征。我们还提出了一个约束恒星伴星的证据，预计在1100 AU的分离，并推测它可能有助于我们怀疑KELT-18的自旋轴和它的行星的轨道轴之间的强烈不一致。下合时间为2457542.524998 +/-0.000416（BJD_TDB），轨道周期为2.8717510 +/-0.0000029天。我们鼓励罗西特-麦克劳克林测量在不久的将来，以确认该系统的可疑的自旋-轨道错位。

英文摘要：

We report the discovery of KELT-18b, a transiting hot Jupiter in a 2.87d orbit around the bright (V=10.1), hot, F4V star BD+60 1538 (TYC 3865-1173-1). We present follow-up photometry, spectroscopy, and adaptive optics imaging that allow a detailed characterization of the system. Our preferred model fits yield a host stellar temperature of 6670+/-120 K and a mass of 1.524+/-0.069 Msun, situating it as one of only a handful of known transiting planets with hosts that are as hot, massive, and bright. The planet has a mass of 1.18+/-0.11 Mjup, a radius of 1.57+/-0.04 Rjup, and a density of 0.377+/-0.040 g/cm^3, making it one of the most inflated planets known around a hot star. We argue that KELT-18b's high temperature and low surface gravity, which yield an estimated ~600 km atmospheric scale height, combined with its hot, bright host make it an excellent candidate for observations aimed at atmospheric characterization. We also present evidence for a bound stellar companion at a projected separation of ~1100 AU, and speculate that it may have contributed to the strong misalignment we suspect between KELT-18's spin axis and its planet's orbital axis. The inferior conjunction time is 2457542.524998 +/-0.000416 (BJD_TDB) and the orbital period is 2.8717510 +/- 0.0000029 days. We encourage Rossiter-McLaughlin measurements in the near future to confirm the suspected spin-orbit misalignment of this system.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

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