THE TRENDS HIGH-CONTRAST IMAGING SURVEY. IV. THE OCCURRENCE RATE OF GIANT PLANETS AROUND M DWARFS
THE TRENDS HIGH-CONTRAST IMAGING SURVEY. IV. THE OCCURRENCE RATE OF GIANT PLANETS AROUND M DWARFS
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DOI：
10.1088/0004-637x/781/1/28
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发表时间：
2013-07
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影响因子：
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通讯作者：
B. Montet;J. Crepp;J. Johnson;A. Howard;G. Marcy
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文献类型：
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作者：
B. Montet;J. Crepp;J. Johnson;A. Howard;G. Marcy
基于多普勒的行星巡天已经发现了许多巨行星，但在几个Au之外是不完整的。在较大的恒星行星分离，通过高对比度成像的直接行星探测已被证明是成功的，但这种技术只对年轻的行星敏感，并且表征依赖于理论演化模型。在这里，我们证明，径向速度测量和高对比度成像可以结合起来，以克服这些问题。通过确定星星径向速度的加速度（长期趋势），可以推断出相隔很远的伴星的存在。通过获得高空间分辨率的后续成像观测，我们排除了这种加速是由具有高统计置信度的恒星双星伴星引起的情况。我们报告的结果从分析的多普勒测量的样本111 M-矮星的中位数为29径向速度观测超过中位数的时间基线为11.8年。通过用自适应光学成像瞄准表现出径向速度加速度（“趋势”）的恒星，我们确定6.5% ± 3.0%的M矮星拥有一个或多个质量为1 < m/MJ < 13和0 < a < 20 Au的伴星。这些结果低于对高质量恒星周围行星出现率的分析。我们发现巨行星的出现率是由恒星质量M和金属丰度F <$[Fe/H]的双幂律描述的，使得。我们的研究结果与引力微透镜测量的行星发生率一致;这项研究代表了第一个与微透镜观测无关的模型比较。
Doppler-based planet surveys have discovered numerous giant planets but are incomplete beyond several AU. At larger star–planet separations, direct planet detection through high-contrast imaging has proven successful, but this technique is sensitive only to young planets and characterization relies upon theoretical evolution models. Here we demonstrate that radial velocity measurements and high-contrast imaging can be combined to overcome these issues. The presence of widely separated companions can be deduced by identifying an acceleration (long-term trend) in the radial velocity of a star. By obtaining high spatial resolution follow-up imaging observations, we rule out scenarios in which such accelerations are caused by stellar binary companions with high statistical confidence. We report results from an analysis of Doppler measurements of a sample of 111 M-dwarf stars with a median of 29 radial velocity observations over a median time baseline of 11.8 yr. By targeting stars that exhibit a radial velocity acceleration (“trend”) with adaptive optics imaging, we determine that 6.5% ± 3.0% of M-dwarf stars host one or more massive companions with 1 < m/MJ < 13 and 0 < a < 20 AU. These results are lower than analyses of the planet occurrence rate around higher-mass stars. We find the giant planet occurrence rate is described by a double power law in stellar mass M and metallicity F ≡ [Fe/H] such that . Our results are consistent with gravitational microlensing measurements of the planet occurrence rate; this study represents the first model-independent comparison with microlensing observations.