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arXiv 1601.02706astro-ph.EP
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在K2活动0和1中两颗经过M矮星附近的温带小行星

Two Small Temperate Planets Transiting Nearby M Dwarfs in K2 Campaigns 0 and 1

Joshua E. Schlieder, Ian J. M. Crossfield, Erik A. Petigura, Andrew W. Howard, Kimberly M. Aller, Evan Sinukoff, Howard T. Isaacson, Benjamin J. Fulton, David R… 展开作者

Joshua E. Schlieder, Ian J. M. Crossfield, Erik A. Petigura, Andrew W. Howard, Kimberly M. Aller, Evan Sinukoff, Howard T. Isaacson, Benjamin J. Fulton, David R. Ciardi, Mickael Bonnefoy, Carl Ziegler, Timothy D. Morton, Sebastien Lepine, Christian Obermeier, Michael C. Liu, Vanessa P. Bailey, Christoph Baranec, Charles A. Beichman, Denis Defrere, Thomas Henning, Philip Hinz, Nicholas Law, Reed Riddle, Andrew Skemer

摘要:

开普勒的主要任务揭示了小行星(<4 R_地球)是常见的,特别是在低质量的M矮星周围。K2,重新定位的开普勒任务,继续探索小恒星周围的小行星。在这里,我们结合K2测光光谱,自适应光学成像,和档案调查图像分析两个小行星轨道附近,现场年龄,M矮星K2-26(EPIC 202083828)和K2-9。K2-26是一个M1.0 +/- 0.5矮人,在K2战役0时有93 +/- 7 pc。我们验证了它的14.5665 d周期的行星,并估计其半径为2.67^+0.46_-0.42 R_地球。K2-9是一个M2.5 +/- 0.5矮人,在K2战役1中的110 +/- 12 pc。K2- 9 b最早由Montet等人在2015年发现;在这里,我们展示了主星的光谱和自适应光学成像,并独立验证和表征了这颗行星。我们的分析表明K2- 9 b是一颗2.25^+0.53_-0.96 R_的地球行星,周期为18.4498 d. K2- 26 b的凌日持续时间太长,与已知恒星半径的圆形轨道不一致。因此,长凌日可能是由于光偏心效应,我们的凌日拟合暗示了偏心轨道。这两颗行星都从它们的主星接收到低的入射通量,估计平衡温度<500 K。K2- 9 b可能接受近似地球的日射。然而,它的主星表现出强烈的银河紫外线辐射,这可能会影响它所拥有的任何大气。K2- 26 b和K2- 9 b是一类研究较少的小行星的代表,它们的温度较低,半径介于地球和海王星之间。这些系统的未来研究可以提供关键的洞察力,在过渡期的整体组成和大气性质的趋势,从硅酸盐为主的挥发性丰富的机构。

英文摘要:

The prime Kepler mission revealed that small planets (<4 R_earth) are common, especially around low-mass M dwarfs. K2, the re-purposed Kepler mission, continues this exploration of small planets around small stars. Here we combine K2 photometry with spectroscopy, adaptive optics imaging, and archival survey images to analyze two small planets orbiting the nearby, field age, M dwarfs K2-26 (EPIC 202083828) and K2-9. K2-26 is an M1.0 +/- 0.5 dwarf at 93 +/- 7 pc from K2 Campaign 0. We validate its 14.5665 d period planet and estimate a radius of 2.67^+0.46_-0.42 R_earth. K2-9 is an M2.5 +/- 0.5 dwarf at 110 +/- 12 pc from K2 Campaign 1. K2-9b was first identified by Montet et al. 2015; here we present spectra and adaptive optics imaging of the host star and independently validate and characterize the planet. Our analyses indicate K2-9b is a 2.25^+0.53_-0.96 R_earth planet with a 18.4498 d period. K2-26b exhibits a transit duration that is too long to be consistent with a circular orbit given the measured stellar radius. Thus, the long transits are likely due to the photoeccentric effect and our transit fits hint at an eccentric orbit. Both planets receive low incident flux from their host stars and have estimated equilibrium temperatures <500 K. K2-9b may receive approximately Earth-like insolation. However, its host star exhibits strong GALEX UV emission which could affect any atmosphere it harbors. K2-26b and K2-9b are representatives of a poorly studied class of small planets with cool temperatures that have radii intermediate to Earth and Neptune. Future study of these systems can provide key insight into trends in bulk composition and atmospheric properties at the transition from silicate dominated to volatile rich bodies.

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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