Institute of Astronomy

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

SpeakerTalk DateTalk Series
Yossi Shvartzvald29 July 2014Across HR 2014 Talks

Abstract

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.

Presentation