Direct Imaging Search for Extrasolar Planets in the Pleiades
Direct Imaging Search for Extrasolar Planets in the Pleiades
复制标题
直接成像搜索昴宿星团中的系外行星
DOI：
10.1093/pasj/65.4.90
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发表时间：
2013
影响因子：
2.3
通讯作者：
et al. (No. 34 of 56 authors)
中科院分区：
文献类型：
--
作者：
Yamamoto;K.;Matsuo;T.;Shibai;H.;et al. (No. 34 of 56 authors)
我们在Subaru望远镜上使用HiCIAO结合自适应光学AO 188，对昴星团（1.25亿年，1.35秒差距）中恒星周围的太阳系外行星进行了成像调查。我们在9颗恒星周围的谱带中发现了13个亮度小于14.5等的伴星。这13颗恒星中有5颗被确认为背景星，通过测量它们的自行。在第二个纪元的观察中没有发现一个，因此不是背景或伴随物体。一个有多个时期的图像，但其自行的精度不足以断定它是否是背景物体。其他四个候选者正在等待第二次观测来确定它们的自行。最后，剩下的两颗被证实是分别围绕HD 23514（G 0）和HII 1348（K5）运行的60颗褐矮星伴星，与先前的研究报告一致。在我们的观测中，在距中心星星15等以外的波段，点源的平均探测极限为20.3等。在此检测极限的基础上，我们计算出的检测效率为90%的行星与6至12木星的质量和一个半长轴为50-1000 Au。因此，我们从径向速度观测中推断出行星质量和半长轴的分布，并采用了Baraffe等人的行星演化模型（，A&A，402，701）。由于没有探测到行星，我们估计这样的行星在昴星团的一颗星星周围的频率低于17.9%（2）。
We carried out an imaging survey for extrasolar planets around stars in the Pleiades (125 Myr, 135 pc) in theandbands using HiCIAO combined with adaptive optics, AO188, on the Subaru telescope. We found 13 companion candidates fainter than 14.5 mag in theband around 9 stars. Five of these 13 were confirmed to be background stars by measurement of their proper motion. One was not found in the second epoch observation, and thus was not a background or companion object. One had multi-epoch images, but the precision of its proper motion was not sufficient to conclude whether it was a background object. Four other candidates are waiting for second-epoch observations to determine their proper motion. Finally, the remaining two were confirmed to be 60brown dwarf companions orbiting around HD 23514 (G0) and HII 1348 (K5), respectively, as had been reported in previous studies. In our observations, the average detection limit for a point source was 20.3 mag in theband beyond 15 from the central star. On the basis of this detection limit, we calculated the detection efficiency to be 90% for a planet with 6 to 12 Jovian masses and a semi-major axis of 50–1000 AU. For this reason we extrapolated the distribution of the planet mass and the semi-major axis derived from radial velocity observations, and adopted the planet evolution model Baraffe et al. (, A&A, 402, 701). Since there was no detection of a planet, we estimated the frequency of such planets to be less than 17.9% (2) around one star of the Pleiades cluster.