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arXiv 1901.04558astro-ph.EP
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K2-291 b:一个岩石超级地球,轨道为2.2天

K2-291 b: A rocky super-Earth in a 2.2 day orbit

Molly R. Kosiarek, Sarah Blunt, Mercedes Lopez-Morales, Ian J. M. Crossfield, Evan Sinukoff, Erik A. Petigura, Erica J. Gonzales, Ennio Poretti, Luca Malavolta,… 展开作者

Molly R. Kosiarek, Sarah Blunt, Mercedes Lopez-Morales, Ian J. M. Crossfield, Evan Sinukoff, Erik A. Petigura, Erica J. Gonzales, Ennio Poretti, Luca Malavolta, Andrew W. Howard, Howard Isaacson, Raphaelle D. Haywood, David R. Ciardi, Makennah Bristow, Andrew Collier Cameron, David Charbonneau, Courtney D. Dressing, Pedro Figueira, Benjamin J. Fulton, Bronwen J. Hardee, Lea A. Hirsch, David W. Latham, Annelies Mortier, Chantanelle Nava, Joshua E. Schlieder, Andrew Vanderburg, Lauren Weiss, Aldo S. Bonomo, Francois Bouchy, Lars A. Buchhave, Adrien Coffinet, Mario Damasso, Xavier Dumusque, Christophe Lovis, Michel Mayor, Giusi Micela, Emilio Molinari, Francesco Pepe, David Phillips, Giampaolo Piotto, Ken Rice, Dimitar Sasselov, Damien Segransan, Alessandro Sozzetti, Stephane Udry, Chris Watson

摘要:

K2-291(EPIC 247418783)是一颗太阳型恒星,半径R_star = 0.899 $\pm$ 0.034 R_sun,质量M_star=0.934 $\pm$ 0.038 M_sun。从K2 C13的观测数据中,我们发现了一颗短周期(P = 2.225177 + 6.6e-5 - 6.8e-5天)的超地球行星(R_p = 1.589+0.095- 0.072R_Earth)。我们用自适应光学成像和光谱学来跟踪这个系统,以获得恒星参数,寻找恒星同伴,并确定行星质量。根据我们在凯克一号上使用HIRES和在国家伽利略望远镜上使用HARPS-N进行的75次径向速度测量,我们将EPIC 247418783 b的质量限制为M_p = 6.49 $\pm$ 1.16 M_Earth。我们发现有必要用高斯过程来模拟相关的恒星活动径向速度信号,以便更准确地模拟恒星噪声对我们数据的影响;高斯过程的加入也提高了质量测量的精度。体积密度为8.84+2.50-2.03 g cm-3,与地球的岩石/铁组成一致,没有实质的气体外壳。这样的外壳,如果在过去存在的话,很可能在恒星生命的第一个十亿年里被光蒸发侵蚀掉了。

英文摘要:

K2-291 (EPIC 247418783) is a solar-type star with a radius of R_star = 0.899 $\pm$ 0.034 R_sun and mass of M_star=0.934 $\pm$ 0.038 M_sun. From K2 C13 data, we found one super-Earth planet (R_p = 1.589+0.095-0.072 R_Earth) transiting this star on a short period orbit (P = 2.225177 +6.6e-5 -6.8e-5 days). We followed this system up with adaptive-optic imaging and spectroscopy to derive stellar parameters, search for stellar companions, and determine a planet mass. From our 75 radial velocity measurements using HIRES on Keck I and HARPS-N on Telescopio Nazionale Galileo, we constrained the mass of EPIC 247418783b to M_p = 6.49 $\pm$ 1.16 M_Earth. We found it necessary to model correlated stellar activity radial velocity signals with a Gaussian process in order to more accurately model the effect of stellar noise on our data; the addition of the Gaussian process also improved the precision of this mass measurement. With a bulk density of 8.84+2.50-2.03 g cm-3, the planet is consistent with an Earth-like rock/iron composition and no substantial gaseous envelope. Such an envelope, if it existed in the past, was likely eroded away by photo-evaporation during the first billion years of the star's lifetime.

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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