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arXiv 1102.3372astro-ph.EP
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HD 5388 b是一颗69 M Jup的伴星,而不是行星

HD 5388 b is a 69 M_Jup companion instead of a planet

Johannes Sahlmann, Christophe Lovis, Didier Queloz, Damien Segransan

摘要:

我们用非标准的依巴谷天体测量解研究了六颗系外行星的宿主恒星,这可能表明了未被识别的轨道运动。使用依巴谷中间天体测量数据,我们检测到HD 5388的天体测量轨道,显著性水平为99.4%(2.7 sigma)。HD 5388是一颗贫金属恒星,2010年发现了一颗最小质量为1.96 M_J的候选行星。我们确定它的轨道倾角为i = 178.3 + 0.4/-0.7度,它的伴星HD 5388 b的质量为M_2 = 69 +/-20 M_J。在3-sigma水平上排除了低于13 M_J的质量。其他作者研究了其他五颗恒星的天体测量运动,发现了两颗行星伴星,一颗恒星伴星和两个统计上不显著的轨道。我们的结论是HD 5388 b不是一颗行星,而很可能是一颗褐矮星伴星。此外,我们发现恒星自转轴和伴星轨道轴的倾角有很大的不同。

英文摘要:

We examined six exoplanet host stars with non-standard Hipparcos astrometric solution, which may be indicative of unrecognised orbital motion. Using Hipparcos intermediate astrometric data, we detected the astrometric orbit of HD 5388 at a significance level of 99.4 % (2.7 sigma). HD 5388 is a metal-deficient star and hosts a planet candidate with a minimum mass of 1.96 M_J discovered in 2010. We determined its orbit inclination to be i = 178.3 +0.4/-0.7 deg and the corresponding mass of its companion HD 5388 b to be M_2 = 69 +/- 20 M_J. The orbit is seen almost face-on and the companion mass lies at the upper end of the brown-dwarf mass range. A mass lower than 13 M_J was excluded at the 3-sigma level. The astrometric motions of the five other stars had been investigated by other authors revealing two planetary companions, one stellar companion, and two statistically insignificant orbits. We conclude that HD 5388 b is not a planet but most likely a brown-dwarf companion. In addition, we find that the inclinations of the stellar rotation axis and the companion's orbital axis differ significantly.

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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