Four Sub-Saturns with Dissimilar Densities: Windows into Planetary Cores and Envelopes
Four Sub-Saturns with Dissimilar Densities: Windows into Planetary Cores and Envelopes
复制标题
四个密度不同的次土星：进入行星核心和外层的窗口
DOI：
10.3847/1538-3881/aa5ea5
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
J. Schlieder
中科院分区：
文献类型：
--
作者：
E. Petigura;E. Sinukoff;E. Lopez;I. Crossfield;A. Howard;J. Brewer;B. Fulton;H. Isaacson;D. Ciardi;S. Howell;M. Everett;E. Horch;L. Hirsch;L. Weiss;J. Schlieder
我们展示了Keck/HIRES径向速度运动的结果，该运动研究了四颗亚土星大小的行星，K2-27b, K2-32b， K2-39b和K2-108b，目的是了解它们的质量，轨道和重元素富集程度。行星的大小相似（= 4.5-5.5），但质量不同（= 16-60），这意味着它们的核心和包层质量不同。K2-32b是质量最小的（），轨道靠近两个亚海王星，周期可公度接近3:2:1。K2-27b和K2-39b的质量分别要大得多，并且没有显示出其他行星存在的迹象。K2-108b的质量最大，这意味着它含有大约≈50的重元素。在给定的大小下，亚土星作为一个种群在行星质量上有很大的多样性。它们在质量和大小之间表现出非常小的相关性；亚土星的范围从≈6-60，与大小无关。我们发现行星质量和主星金属丰度之间有很强的相关性，这表明富含金属的圆盘形成了更大质量的行星核心。最大质量的亚土星往往缺乏探测到的伴星，并且轨道偏心率适中，这可能是由于之前的动力不稳定时期造成的。最后，我们观察到行星包层分数与当前平衡温度之间只有微弱的相关性，这表明光蒸发在确定亚土星从其原行星盘吸积的气体量方面并不起主导作用。
We present results from a Keck/HIRES radial velocity campaign to study four sub-Saturn-sized planets, K2-27b, K2-32b, K2-39b, and K2-108b, with the goal of understanding their masses, orbits, and heavy-element enrichment. The planets have similar sizes ( = 4.5–5.5 ), but have dissimilar masses ( = 16–60 ), implying a diversity in their core and envelope masses. K2-32b is the least massive ( ) and orbits in close proximity to two sub-Neptunes near a 3:2:1 period commensurability. K2-27b and K2-39b are significantly more massive at and , respectively, and show no signs of additional planets. K2-108b is the most massive at , implying a large reservoir of heavy elements of about ≈50 . Sub-Saturns as a population have a large diversity in planet mass at a given size. They exhibit remarkably little correlation between mass and size; sub-Saturns range from ≈6–60 , regardless of size. We find a strong correlation between planet mass and host star metallicity, suggesting that metal-rich disks form more massive planet cores. The most massive sub-Saturns tend to lack detected companions and have moderately eccentric orbits, perhaps as a result of a previous epoch of dynamical instability. Finally, we observe only a weak correlation between the planet envelope fraction and present-day equilibrium temperature, suggesting that photo-evaporation does not play a dominant role in determining the amount of gas sub-Saturns accrete from their protoplanetary disks.
Kepler-2.0 任务的精确时间序列光度测量
影响因子：
4.8
作者：
Aigrain S
通讯作者：
Aigrain S
开普勒数据集中的独立行星搜索 - II 开普勒 87 周围的极低密度超级地球质量行星
影响因子：
6.5
作者：
Dreizler;Stefan;Zechmeister;Mathias;Husser;Tim-Oliver
通讯作者：
Tim-Oliver