Unbound or distant planetary mass population detected by gravitational microlensing
Unbound or distant planetary mass population detected by gravitational microlensing
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DOI：
10.1038/nature10092
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发表时间：
2011-05
期刊：
影响因子：
64.8
通讯作者：
T. K. D. P. I. A. F. C. S. A. K. J. B. Y. P. M. A. W. Sumi Kamiya Bennett Bond Abe Botzler Fukui Furusaw-T.-K.-D.-P.-I.-A.-F.-C.-S.-A.-K.-J.-B.-Y.-P.-M.-A.;T. Sumi;K. Kamiya;D. Bennett;I. Bond-I.-Bo
中科院分区：
文献类型：
--
作者：
T. K. D. P. I. A. F. C. S. A. K. J. B. Y. P. M. A. W. Sumi Kamiya Bennett Bond Abe Botzler Fukui Furusaw-T.-K.-D.-P.-I.-A.-F.-C.-S.-A.-K.-J.-B.-Y.-P.-M.-A.;T. Sumi;K. Kamiya;D. Bennett;I. Bond-I.-Bo
自1995年以来，已经有500多颗系外行星被不同的技术探测到，其中12颗是用引力微透镜探测到的。它们中的大多数都受到其宿主恒星的引力束缚。有一些证据表明，在年轻的恒星形成区存在自由漂浮的行星质量天体，但这些天体仅限于3至15木星质量的大质量天体，在光度质量估计及其丰度方面存在很大的不确定性。在这里，我们报告了一个人口的发现未绑定或遥远的恒星质量的对象，这几乎是两倍（）作为主序星常见的，根据两年的引力微透镜调查观测银河隆起。这些行星质量的天体没有可以通过引力微透镜在大约10个天文单位内探测到的宿主恒星。然而，与直接成像的限制进行比较表明，这些行星质量的物体中的大多数并不与任何宿主星星绑定。质量函数在大约一个木星质量处的突然变化支持了它们的形成过程与恒星和棕矮星不同的想法。它们可能在原行星盘中形成，随后分散到未绑定或非常遥远的轨道上。
Since 1995, more than 500 exoplanets have been detected using different techniques,, of which 12 were detected with gravitational microlensing,. Most of these are gravitationally bound to their host stars. There is some evidence of free-floating planetary-mass objects in young star-forming regions,,,, but these objects are limited to massive objects of 3 to 15 Jupiter masses with large uncertainties in photometric mass estimates and their abundance. Here, we report the discovery of a population of unbound or distant Jupiter-mass objects, which are almost twice () as common as main-sequence stars, based on two years of gravitational microlensing survey observations towards the Galactic Bulge. These planetary-mass objects have no host stars that can be detected within about ten astronomical units by gravitational microlensing. However, a comparison with constraints from direct imaging suggests that most of these planetary-mass objects are not bound to any host star. An abrupt change in the mass function at about one Jupiter mass favours the idea that their formation process is different from that of stars and brown dwarfs. They may have formed in proto-planetary disks and subsequently scattered into unbound or very distant orbits.