Institute of Astronomy

The frequency of snowline planets from a second-generation microlensing survey

SpeakerTalk DateTalk Series
Yossi Shvartzvald29 July 2014Across HR 2014 Talks


Among the techniques currently used to discover extrasolar planets, microlensing has a unique sensitivity to planets beyond the ""snowline"", where gas and ice giants are likely to form. Starting April 2011, we have begun a ""second generation"" microlensing survey, combining OGLE, MOA, and the Wise observatory, in which 8 deg^2 of the Galactic Bulge are monitored round the clock, for several months each year. I will present a statistical analysis for the first three seasons of the survey. Over 10% of the events that were observed by all three sites showed a deviation from a single-lens microlensing, and for almost 1/3 of those the anomaly might be explained by a planetary companion. By accounting for our detection efficiency, we find a ~20% planetary system abundance. Moreover, our results suggests that massive planets around low-mass stars are common, which may be in conflict with planetary formation scenarios. The data also can set constraints on the multiplicity fraction and on the binary mass ratio distribution.