标题： 可能的碳丰富的内部结构在超级地球55 Cancri e 显示英文标题

标题： A Possible Carbon-rich Interior in Super-Earth 55 Cancri e

摘要： 地球行星在太阳系中，如地球，是富氧的，硅酸盐和铁是它们内部最常见的矿物。 然而，围绕其他恒星运行的岩石行星的真实化学多样性尚不清楚。 质量与半径测量用于限制超级地球（质量为1至10倍地球质量的系外行星）的内部组成，并通常用假设以地球为中心的富氧组成的行星内部模型进行解释。 使用此类模型，超级地球55 Cancri e（质量为8倍地球质量，半径为2倍地球半径）被认为可能具有由铁、硅酸盐和一个（质量占比≥10%）超临界水包层组成的内部结构。 我们报告称，55 Cancri e的质量和半径也可以通过一个由铁、碳、碳化硅和/或硅酸盐组成的富碳固态内部来解释，而没有挥发性包层。 虽然数据允许铁的质量分数高达40%，但碳、碳化硅和/或硅酸盐的质量分数有很宽的可能范围。 如果其原行星盘的成分与其宿主恒星相同，那么55 Cancri e富碳的可能性也是合理的，该宿主恒星已被报道为富碳。 然而，需要更精确的恒星元素丰度估计和对行星大气的观测，以进一步限制其内部组成。 与太阳系中的类地行星相比，55 Cancri e可能存在富碳内部，这为地外岩石行星开辟了一个新的地球化学和地球物理领域。 显示英文摘要

摘要： Terrestrial planets in the solar system, such as the Earth, are oxygen-rich, with silicates and iron being the most common minerals in their interiors. However, the true chemical diversity of rocky planets orbiting other stars is yet unknown. Mass and radius measurements are used to constrain the interior compositions of super-Earths (exoplanets with masses of 1 - 10 Earth masses), and are typically interpreted with planetary interior models that assume Earth-centric oxygen-rich compositions. Using such models, the super-Earth 55 Cancri e (mass of 8 Earth masses, radius of 2 Earth radii) has been suggested to bear an interior composition consisting of Fe, silicates, and an envelope (>= 10% by mass) of super-critical water. We report that the mass and radius of 55 Cancri e can also be explained by a carbon-rich solid interior made of Fe, C, SiC, and/or silicates and without a volatile envelope. While the data allow Fe mass fractions of up to 40%, a wide range of C, SiC and/or silicate mass fractions are possible. A carbon-rich 55 Cancri e is also plausible if its protoplanetary disk bore the same composition as its host star, which has been reported to be carbon-rich. However, more precise estimates of the stellar elemental abundances and observations of the planetary atmosphere are required to further constrain its interior composition. The possibility of a C-rich interior in 55 Cancri e opens a new regime of geochemistry and geophysics in extraterrestrial rocky planets, compared to terrestrial planets in the solar system.