The frequency of snowline planets from a 2 nd generation microlensing survey Yossi Shvartzvald Tel-Aviv University with Dan Maoz, Matan Friedmann (TAU) in collaboration with OGLE, MOA, µfun
Microlensing basics Amplification ~milliarcsec
Microlensing basics S. Gaudi
Microlensing basics S. Gaudi
Microlensing Surveys - 1 st Generation Survey challenge: Galactic bulge event probability ~10-6 Monitor many stars, low cadence OGLE, Chile, 1.3m MOA, NZ, 1.8m
Microlensing Surveys - 1 st Generation ~ 650 events/year
Microlensing Surveys - 1 st Generation Follow-Up Network on bright, high-magnification events: higher sensitivity to planets high S/N light curves OGLE, Chile, 1.3m MOA, NZ, 1.8m
Microlensing Surveys - 1 st Generation Bond et al. 2004
Microlensing Surveys - 1 st Generation Gould et al. 2006 Udalski et al. 2005 Gaudi et al. 2008
Microlensing statistics Microlensing probes a unique region of planetary parameter-space Gould et al. 2006,2009
Microlensing statistics near the Einstein radii of stars ~ their snow lines. Snowline scaling with mass: R M Lens S Gould et al. 2006,2009
Microlensing statistics snowline planet frequency Gould et al. 2010 (6 planets): ~1/3 of stars have snowline-region giant planets ~1/6 of stars have solar-like planetary systems Sumi et al. 2010 (10 planets): Neptunes are at least 3 times more common than Jupiters Cassan et al. 2012 (3 planets+gould10+sumi10): ~1/6 host Jupiters ~1/2 host Neptunes ~2/3 host super-earths
Microlensing Surveys - 1 st Generation But only 16 planets detected (2003-2010) Why?
Microlensing Surveys - 1 st Generation But only 16 planets detected (2003-2010) Why? High magnification events are rare events (~1%) ~7 events/year ~2 planets/year
Microlensing Surveys - 1 st Generation But only 16 planets detected (2003-2010) Why? High magnification events are rare events (~1%) ~7 events/year ~2 planets/year Solution: Generation II microlensing survey
Second generation microlensing survey Wise Obs., Israel, 1m OGLE, Chile, 1.3m MOA, NZ, 1.8m
The generation-ii network
The generation-ii network Group OGLE
The generation-ii network Group OGLE MOA
The generation-ii network Group OGLE MOA WISE
Second generation microlensing survey 8 deg 2 of bulge with highest lensing rate covered quasi-continuously by all 3 telescopes cadences 20-40 min
Gen-II planets First ML planet in the habitable zone MOA-11-293 M P L 4.8 0.3M a 1.1 0.1 AU M 0.86 0.06 M J I-band (mag) I-band (mag) OGLE MOA Wise Survey data only All data Batista et al. 2013 HJD-2450000 Yee, Shvartzvald et al. 2012
Earth at ~1 AU from one member of a 15 AU binary Gen-II planets OGLE-13-341 Gould et al., Science 2014
Super-Jupiter around M dwarf Gen-II planets M MOA-11-322 P L 11.6 1.5 1.2 0.39 13.4 5.6 a 4.3 AU M 0.45 0.19 M M J Shvartzvald et al. 2014
Gen-II planets Jupiter around M dwarf OGLE-12-406 M P 2.73 0.43M a 3.45 0.26 AU M L 0.44 0.07 M J Poleski et al. 2014, Tsapras et al. 2014
Gen-II planets Saturn/Jupiter around M dwarf OGLE-11-265 M 0.34 0.80 M M P a 1.09 1.85 AU L 0.09 0.20 M J Udalski et al. in prep
Gen-II planets Cold Jupiters around low-mass stars are common?
What to expect from Generation II? a simulation: Simulating the experiment Monte-Carlo of many Solar-System-like planetary systems, host star properties matching those of bulge microlensing population, random inclinations. Shvartzvald & Maoz 2012
Simulation results: can detect ~15-20% of planets around microlensed stars; Simulating the experiment S Shvartzvald & Maoz 2012
2011-2013 sample Sample Events 167
Anomalous events Sample Anomalous Planetary Events 167 27 (16.3%) 8 (4.8%) Mass ratio
Anomalous events Sample Anomalous Planetary Events 167 27 (16.3%) 8 (4.8%) Mass ratio Accounting for detection efficiency, >24% snowline planet frequency
Conclusions 2 nd generation microlening survey: A controlled experiment for the abundance of planets at a few AU Cold Jupiters around low-mass stars are common (?) Preliminary results suggest a lower limit of 24% snowline planet frequency