THE MASS OF Kepler-93b AND THE COMPOSITION OF TERRESTRIAL PLANETS-猫眼课题宝

DOI：

10.1088/0004-637x/800/2/135

发表时间：

2014-12

期刊：

The Astrophysical Journal

影响因子：

通讯作者：

中科院分区：

其他

文献类型：

作者：

C. Dressing;D. Charbonneau;X. Dumusque;S. Gettel;F. Pepe;A. Collier Cameron;D. Latham;E. Molinari;S. Udry;L. Affer;A. Bonomo;L. Buchhave;R. Cosentino;P. Figueira;A. Fiorenzano;A. Harutyunyan;R. Haywood;J. Johnson;M. López-Morales;C. Lovis;L. Malavolta;M. Mayor;G. Micela;F. Motalebi;V. Nascimbeni;D. Phillips;G. Piotto;D. Pollacco;D. Queloz;K. Rice;D. Sasselov;D. Ségransan;A. Sozzetti;A. Szentgyorgyi;C. Watson

开普勒 - 93b是一颗半径为\(1.478\pm0.019\)倍地球半径（\(R_{\oplus}\)）的行星，它围绕一颗明亮（视星等\(V = 10.2\)）且通过星震学方法确定了特征的主恒星运行，其公转周期为\(4.7\)天。主恒星质量为\(0.911\pm0.033\)倍太阳质量（\(M_{\odot}\)），半径为\(0.919\pm0.011\)倍太阳半径（\(R_{\odot}\)）。基于使用伽利略国家望远镜上的HARPS - N光谱仪获得的\(86\)次径向速度观测以及\(32\)次凯克望远镜/高分辨率阶梯光栅光谱仪（HIRES）的存档观测，我们给出了一个精确的质量估计值为\(4.02\pm0.68\)倍地球质量（\(M_{\oplus}\)）。相应的高密度为\(6.88\pm1.18\)克/立方厘米，这与主要由铁和硅酸镁组成的岩石成分相符。我们将开普勒 - 93b与其他参数精确限定的高密度行星进行比较，发现在\(1\)到\(6\)倍地球质量之间，所有高密度行星，包括地球和金星，都可以用相同的铁与硅酸镁的固定比例很好地描述。到目前为止，还没有质量大于\(6\)倍地球质量的此类行星的例子。在这个质量范围内的所有已知行星密度都较低，需要大量的挥发物或氢/氦气体。我们还根据长期径向速度趋势和存档的自适应光学图像确定了开普勒 - 93系统中外围伴星的质量和公转周期。随着质量和半径精确限定的高密度行星样本不断增加，我们将能够检验本文所考虑的七颗高密度行星所发现的固定成分模型是否适用于\(1 - 6\)倍地球质量的所有行星。

Kepler-93b is a 1.478 ± 0.019 R⊕ planet with a 4.7 day period around a bright (V = 10.2), astroseismically characterized host star with a mass of 0.911 ± 0.033 M☉ and a radius of 0.919 ± 0.011 R☉. Based on 86 radial velocity observations obtained with the HARPS-N spectrograph on the Telescopio Nazionale Galileo and 32 archival Keck/HIRES observations, we present a precise mass estimate of 4.02 ± 0.68 M⊕. The corresponding high density of 6.88 ± 1.18 g cm−3 is consistent with a rocky composition of primarily iron and magnesium silicate. We compare Kepler-93b to other dense planets with well-constrained parameters and find that between 1 and 6 M⊕, all dense planets including the Earth and Venus are well-described by the same fixed ratio of iron to magnesium silicate. There are as of yet no examples of such planets with masses >6 M⊕. All known planets in this mass regime have lower densities requiring significant fractions of volatiles or H/He gas. We also constrain the mass and period of the outer companion in the Kepler-93 system from the long-term radial velocity trend and archival adaptive optics images. As the sample of dense planets with well-constrained masses and radii continues to grow, we will be able to test whether the fixed compositional model found for the seven dense planets considered in this paper extends to the full population of 1–6 M⊕ planets.

THE MASS OF Kepler-93b AND THE COMPOSITION OF TERRESTRIAL PLANETS

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