Masses for free-floating planets and dwarf planets  

作　　者：Andrew Gould Wei-Cheng Zang Shude Mao Su-Bo Dong Andrew Gould;臧伟呈;毛淑德;东苏勃(Max-Planck-Institute for Astronomy,Konigstuhl 17,D-69117 Heidelberg,Germany;Department of Astronomy,Ohio State University,140 W.18th Ave.,Columbus,OH 43210,USA;Department of Astronomy,Tsinghua University,Beijing 100084,China;National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China;Kavli Institute for Astronomy and Astrophysics,Peking University,Beijing 100871,China)

机构地区：[1]Max-Planck-Institute for Astronomy,Konigstuhl 17,D-69117 Heidelberg,Germany [2]Department of Astronomy,Ohio State University,140 W.18th Ave.,Columbus,OH 43210,USA [3]Department of Astronomy,Tsinghua University,Beijing 100084,China [4]National Astronomical Observatories,Chinese Academy of Sciences,Beijing 100101,China [5]Kavli Institute for Astronomy and Astrophysics,Peking University,Beijing 100871,China

出　　处：《Research in Astronomy and Astrophysics》2021年第6期207-221,共15页天文和天体物理学研究（英文版）

基　　金：support by the National Science Foundation of China (Grant Nos. 11821303 and 11761131004);supported by National Key R&D Program of China No.2019YFA0405100。

摘　　要：The mass and distance functions of free-floating planets(FFPs) would give major insights into the formation and evolution of planetary systems, including any systematic differences between those in the disk and bulge. We show that the only way to measure the mass and distance of individual FFPs over a broad range of distances is to observe them simultaneously from two observatories separated by D ~ O(0.01 au)(to measure their microlens parallax πE) and to focus on the finite-source point-lens(FSPL) events(which yield the Einstein radius θE). By combining the existing KMTNet 3-telescope observatory with a 0.3 m 4 deg2 telescope at L2, of order 130 such measurements could be made over four years, down to about M ~ 6 M⊕for bulge FFPs and M ~ 0.7 M⊕for disk FFPs. The same experiment would return masses and distances for many bound planetary systems. A more ambitious experiment, with two 0.5 m satellites(one at L2 and the other nearer Earth) and similar camera layout but in the infrared, could measure masses and distances of sub-Moon mass objects, and thereby probe(and distinguish between) genuine sub-Moon FFPs and sub-Moon "dwarf planets" in exo-Kuiper Belts and exo-Oort Clouds.

关 键 词：gravitational lensing:micro 

分 类 号：P15[天文地球—天文学]