FREE-FLOATING PLANETS, THE EINSTEIN DESERT, AND 'OUMUAMUA

被引：33

作者：

Gould, Andrew ^{[1
,2
]}

Jung, Youn Kil ^{[3
,4
]}

Hwang, Kyu-Ha ^{[3
]}

Dong, Subo ^{[5
]}

Albrow, Michael D. ^{[6
]}

Chung, Sun-Ju ^{[3
]}

Han, Cheongho ^{[7
]}

Ryu, Yoon-Hyun ^{[3
]}

Shin, In-Gu ^{[7
]}

Shvartzvald, Yossi ^{[8
]}

Yang, Hongjing ^{[9
]}

Yee, Jennifer C. ^{[10
]}

Zang, Weicheng ^{[9
]}

Cha, Sang-Mok ^{[3
,11
]}

Kim, Dong-Jin ^{[3
]}

Kim, Seung-Lee ^{[3
,4
]}

Lee, Chung-Uk ^{[3
]}

Lee, Dong-Joo ^{[3
]}

Lee, Yongseok ^{[3
,11
]}

Park, Byeong-Gon ^{[3
,4
]}

Pogge, Richard W. ^{[2
]}

机构：

[1] Max Planck Inst Astron, Konigstuhl 17, D-69117 Heidelberg, Germany

[2] Ohio State Univ, Dept Astron, 140 W 18th Ave, Columbus, OH 43210 USA

[3] Korea Astron & Space Sci Inst, Daejon 34055, South Korea

[4] Univ Sci & Technol UST, 217 Gajeong Ro, Daejeon 34113, South Korea

[5] Peking Univ, Kavli Inst Astron & Astrophys, Yi He Yuan Rd 5, Beijing 100871, Peoples R China

[6] Univ Canterbury, Dept Phys & Astron, Private Bag 4800, Christchurch 8020, New Zealand

[7] Chungbuk Natl Univ, Dept Phys, Cheongju 28644, South Korea

[8] Weizmann Inst Sci, Dept Particle Phys & Astrophys, IL-76100 Rehovot, Israel

[9] Tsinghua Univ, Dept Astron, Beijing 100084, Peoples R China

[10] Ctr Astrophys Harvard & Smithsonian, 60 Garden St, Cambridge, MA 02138 USA

[11] Kyung Hee Univ, Sch Space Res, Yongin 17104, Kyeonggi, South Korea

来源：

JOURNAL OF THE KOREAN ASTRONOMICAL SOCIETY | 2022年 / 55卷 / 05期

基金：

美国国家科学基金会; 新加坡国家研究基金会;

关键词：

gravitational lensing; micro; minor planets; asteroids; general; planets and satellites; detection; MICROLENSING EVENTS; ORIGIN; PHOTOMETRY; CANDIDATE; OORT;

D O I：

10.5303/JKAS.2022.55.5.173

中图分类号：

P1 [天文学];

学科分类号：

0704 ;

摘要：

We complete the survey for finite-source/point-lens (FSPL) giant-source events in 2016-2019 KMTNet microlensing data. The 30 FSPL events show a clear gap in Einstein radius, 9 mu as < BE < 26 mu as, which is consistent with the gap in Einstein timescales near tE similar to 0.5 days found by Mrcz et al. (2017) in an independent sample of point-source/point-lens (PSPL) events. We demonstrate that the two surveys are consistent. We estimate that the 4 events below this gap are due to a power-law distribution of free-floating planet candidates (FFPs) dNFFP/d log M = (0.4 +/- 0.2) (M/38 M circle plus)-P/star, with 0.9 < p < 1.2. There are substantially more FFPs than known bound planets, implying that the bound planet power-law index gamma = 0.6 is likely shaped by the ejection process at least as much as by formation. The mass density per decade of FFPs in the Solar neighborhood is of the same order as that of 'Oumuamua-like objects. In particular, if we assume that 'Oumuamua is part of the same process that ejected the FFPs to very wide or unbound orbits, the power-law index is p = 0.89 +/- 0.06. If the Solar System's endowment of Neptune-mass objects in Neptune-like orbits is typical, which is consistent with the results of Poleski et al. (2021), then these could account for a substantial fraction of the FFPs in the Neptune-mass range.

引用

页码：173 / 194

页数：22

共 56 条

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