A high-precision chemical abundance analysis of the HAT-P-1 stellar binary: constraints on planet formation
A high-precision chemical abundance analysis of the HAT-P-1 stellar binary: constraints on planet formation
复制标题
HAT-P-1 恒星双星的高精度化学丰度分析：行星形成的限制
DOI：
10.1093/mnrasl/slu055
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发表时间：
2014
影响因子：
4.8
通讯作者：
J. Meléndez
中科院分区：
文献类型：
--
作者：
Fan Liu;M. Asplund;I. Ramírez;D. Yong;J. Meléndez
我们基于高分辨率、高信噪比的Keck/HIRES光谱，对HAT-P-1双星进行了高精度、差异元素丰度分析。这个双星系统中的副恒星已知有一颗凌日巨行星，而在主星周围还没有发现行星。主、次星的金属丰度（[Fe/H]）在误差范围内相同，分别为$0.146 \pm 0.014$指数（$\sigma$ = 0.033指数）和$0.155 \pm 0.007$指数（$\sigma$ = 0.023指数）。测量了23种元素极其精确的丰度比（平均误差为$\sigma$ ([X/Fe]) = 0.013指数），发现两颗恒星之间无法区分：$\Delta$ [X/Fe]（次级-主）= $+0.001 \pm 0.006$指数（$\sigma$ = 0.008指数）。HAT-P-1中两颗恒星组成的化学成分惊人的相似，与16 Cyg A+B中可能存在的0.04指数水平的差异相反，16 Cyg A+B也拥有一颗巨大的行星，其质量至少是HAT-P-1副恒星周围行星的3倍。我们的结论是，巨行星的存在并不一定意味着主星的化学成分不同。HAT-P-1中每颗恒星相对于太阳的元素丰度与元素的凝结温度呈相同的正相关；因此，它们的丰度模式与在大多数太阳双胞胎中观察到的非常相似。鉴于Melendez等人（2009）对太阳丰度模式的解释，我们得出结论，HAT-P-1的类地行星形成效率低于太阳。这与“近距离巨行星的存在会阻止类地行星的形成或生存”的预期是一致的。
We present a high-precision, differential elemental abundance analysis of the HAT-P-1 stellar binary based on high-resolution, high signal-to-noise ratio Keck/HIRES spectra. The secondary star in this double system is known to host a transiting giant planet while no planets have yet been detected around the primary star. The derived metallicities ([Fe/H]) of the primary and secondary stars are identical within the errors: $0.146 \pm 0.014$ dex ($\sigma$ = 0.033 dex) and $0.155 \pm 0.007$ dex ($\sigma$ = 0.023 dex), respectively. Extremely precise differential abundance ratios of 23 elements have been measured (mean error of $\sigma$([X/Fe]) = 0.013 dex) and are found to be indistinguishable between the two stars: $\Delta$[X/Fe] (secondary - primary) = $+0.001 \pm 0.006$ dex ($\sigma$ = 0.008 dex). The striking similarity in the chemical composition of the two stellar components in HAT-P-1 is contrary to the possible 0.04 dex level difference seen in 16 Cyg A+B, which also hosts a giant planet, at least 3 times more massive than the one around HAT-P-1 secondary star. We conclude that the presence of giant planets does not necessarily imply differences in the chemical compositions of the host stars. The elemental abundances of each star in HAT-P-1 relative to the Sun show an identical, positive correlation with the condensation temperature of the elements; their abundance patterns are thus very similar to those observed in the majority of solar twins. In view of the Melendez et al. (2009)'s interpretation of the peculiar solar abundance pattern, we conclude that HAT-P-1 experienced less efficient formation of terrestrial planets than the Sun. This is in line with the expectation that the presence of close-in giant planets preventing the formation or survival of terrestrial planets.