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MOA-II microlensing exoplanet survey

MOA-II microlensing exoplanet survey. Takahiro Sumi (Nagoya univ.) the MOA collaboration. planetary microlensing. Sensitivity of various methods. RV transit Direct image Microlensing ： not rely on flux from host. small planet ：　 down to Earth

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MOA-II microlensing exoplanet survey

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  1. MOA-II microlensing exoplanet survey Takahiro Sumi (Nagoya univ.) the MOA collaboration

  2. planetary microlensing

  3. Sensitivity of various methods • RV • transit • Direct image • Microlensing： • not rely on flux from host • small planet：　down to Earth • 1-6 AU ： around snow line • Faint star :M-dwarf, brown dwarf • No host ：　free floating planet • Far system:　galactic distribution Credit Bennett

  4. Sensitivity of microlensing

  5. Microlensing observation global network Survey Group Follow-up Group Micro lensing Alert  • PLANET • FUN • Pointing each candidate • High cadence MOA(NewZealand) OGLE(Chile), (no observation in 2009) • Wide field • Low cadence Anomaly Alert 

  6. MOA (since 1995)（Microlensing Observation in Astrophysics）（ New Zealand/Mt. John Observatory, Latitude：44S, Alt: 1029m） Mirror : 1.8m CCD : 80M pix. FOV : 2.2 deg.2

  7. MOA (until ~1500)（the world largest bird in NZ） • height:3.5ｍ • weight:240kg • can not fly • Extinct 500 years ago （Maori ate them)

  8. Observation by MOA • 50 deg.2(20Mstars) • 1obs./night.(>MJup) • 1obs./95min.(Mjup) • 1obs./47min. (Mnep) • 1obs./15min. (M) G.C. 489events(3planets) (16/9/2009) http://www.massey.ac.nz/~iabond/alert/alert.html

  9. Real-time Anomaly check at Mt.John The planet found on 11/9/2009 anomaly

  10. The first planet via microlensingOGLE 2003-BLG-235/MOA 2003-BLG-53 Mass： ~3MJ, Sep. : ~4AU

  11. :OGLE 2005-BLG-71 (Udalski, et. al.2006 Dong et al. 2008) 2nd Exoplanet Discovery by lensing • ML=0.46±0.04 • DL=3.3±0.4kpc • Mp=3.5±0.3MJ • Sep=3.6±0.2AU • V~103km/s (HST) Data from OGLE, FUN, PLANET & MOA The most massive Planet at wide sep for M-dwarf Challenging to form in core-accretion model Thick disk

  12. 5.5 Earth mass:OGLE-2005-BLG-390 Sep~3AU • Proved • microlensing • is sensitive to • Super earth The smallest Planet！(at that time) (Beaulieu et al. 2006, Nature,439,437)

  13. Jupiter/Saturn analog : OGLE-2006-BLG-109L ２５multiple system Host mass Habitable zone snow line giant planets are supposed to form outside of snow line, but not observed First case that both giant planets are outside of snow line OGLE-2006-BLG-109L Jupiter, Saturn

  14. The smallest host star：MOA 2007-BLG-192 Bennett et al. 2008 With planet No planet Mhost=0.06 (0.024-0.128) M Mp =3.3 (1.0-17.8)MEarth MOA OGLE VLT-NACO(AO) image Lens is faint: Late M-dwarf or brown dwarf Can be determined by HST 5 years later No flux from Lens

  15. Summary of Planet candidates Gould et al. 2006: “Cool Neptune” are common in K,M-dwarf：~40% (>16% at 90% confidence.)” preliminary. Credit Bennett consistent with formation theory. (Ida & Lin, 2004)

  16. Host mass Galactic distribution Uniform in DL >60% of lensing events are due to bulge lens Sun GC Distance Density distribution Few Planets in GB!? (be careful: there may be Observational bias)

  17. Free floating planet Planet scattering Simulation by Veras et al. 2009 • half planets rejected after 108yr • Free floating • Microlensing can find tE=1.2days ~1MJ

  18. summary • 9 exoplanets (8system) via microlensing published 3 exoplanets in preparation. • MOA is the only survey group in 2009 (489events so far) 3(+2) exoplanets candidates in 2009 so far. • Unique planets: • The largest Giant planet at wide sep. around M-dwarf in Thick disk • Jupiter/Saturn analog • Exoplanet around Brown dwarf • ”Cool Neptune“ are common in K,M-dwarf • Evidence of few exoplanets in the bulge?? • Free floating planets • Earth Mass planet soon!

  19. end

  20. OGLE-2007-BLG-368 (MOA-2007-BLG-308) q=1x10^-4, sep= 0.9RE Keck, AO, K-band OGLE, I-band

  21. Planetary microlensing

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