ヨネハラ アツノリ   YONEHARA ATSUNORI
  米原 厚憲
   所属   京都産業大学  理学部 宇宙物理・気象学科
   職種   教授
言語種別 英語
発行・発表の年月 2016/04
形態種別 研究論文
査読 査読あり
標題 The frequency of snowline-region planets from four-years of OGLE-MOA-Wise second-generation microlensing
執筆形態 その他
掲載誌名 Monthly Notices of the Royal Astronomical Society
巻・号・頁 457(4),pp.4089-4113
著者・共著者 Y. Shvartzvald,D. Maoz,A. Udalski,T. Sumi,M. Friedmann,S. Kaspi,R. Poleski,M. K. Szymański,J. Skowron,S. Kozłowski,Ł. Wyrzykowski,P. Mróz,P. Pietrukowicz,G. Pietrzyński,I. Soszyński,K. Ulaczyk,F. Abe,R. K. Barry,D. P. Bennett,A. Bhattacharya,I. A. Bond,M. Freeman,K. Inayama,Y. Itow,N. Koshimoto,C. H. Ling,K. Masuda,A. Fukui,Y. Matsubara,Y. Muraki,K. Ohnishi,N. J. Rattenbury,To. Saito,D. J. Sullivan,D. Suzuki,P. J. Tristram,Y. Wakiyama,A. Yonehara
概要 We present a statistical analysis of the first four seasons from a<br />
&quot;second-generation&quot; microlensing survey for extrasolar planets, consisting of<br />
near-continuous time coverage of 8 deg$^2$ of the Galactic bulge by the OGLE,<br />
MOA, and Wise microlensing surveys. During this period, 224 microlensing events<br />
were observed by all three groups. Over 12% of the events showed a deviation<br />
from single-lens microlensing, and for $\sim$1/3 of those the anomaly is likely<br />
caused by a planetary companion. For each of the 224 events we have performed<br />
numerical ray-tracing simulations to calculate the detection efficiency of<br />
possible companions as a function of companion-to-host mass ratio and<br />
separation. Accounting for the detection efficiency, we find that<br />
$55^{+34}_{-22}\%$ of microlensed stars host a snowline planet. Moreover, we<br />
find that Neptunes-mass planets are $\sim10$ times more common than<br />
Jupiter-mass planets. The companion-to-host mass ratio distribution shows a<br />
deficit at $q\sim10^{-2}$, separating the distribution into two companion<br />
populations, analogous to the stellar-companion and planet populations, seen in<br />
radial-velocity surveys around solar-like stars. Our survey, however, which<br />
probes mainly lower-mass stars, suggests a minimum in the distribution in the<br />
super-Jupiter mass range, and a relatively high occurrence of brown-dwarf<br />
companions.
DOI 10.1093/mnras/stw191
arXiv ID arXiv:1510.04297
PermalinkURL http://arxiv.org/abs/1510.04297v2