Searching for Frozen super Earth mass planet via microlensing. Jean-Philippe Beaulieu, Institut d’Astrophysique de Paris PLANET/ROBONET collaboration HOLMES : Hunting fOr Low Mass Extrasolar Planets Funded by Agence Nationale de la Recherche, France ( ) See also contributions by J. Donatowicz (TU Wien), S. Gaudi (Ohio)

1-7 kpc from Sun Galactic centerSun 8 kpc Light curve Source star and images Lens star and planet Observer Target Field in the Central Galactic Bulge Currently, OGLE-III and MOA-II

Unveiling a planetary companion

1995 : No planet detected so far. Microlensing seemed to be a cool and easy Jupiter hunting method… Gould et Loeb 1992 : « Planets in a solar-like system positioned half-way to the Galactic center should leave a noticeable signature (magnification larger than 5 percent) on the light curve of a gravitationally lensed bulge star in about 20 percent of the microlensing events. »

If planetary Einstein Ring < source star disk: planetary microlensing effect is washed out (Bennett & Rhie 1996) For a typical bulge giant source star, the limiting mass is ~10 M  For a bulge, solar type main sequence star, the limiting mass is ~ 0.1 M  Earth mass planet signal is washed out for giant source stars Need to monitor small stars to get low mass planets. 1996, sensitivity to Earths depends on source size

Using high magnification events, Griest & Safizadeh 1998 « We show that by focusing on high-magnification events, the probability of detecting planets of Jupiter mass or greater in the lensing zone [( ) R E ] is nearly 100%, with the probability remaining high down to Saturn masses and substantial even at 10 Earth masses. » Detection ≠ characterization Planetary caustic Central caustic

Hunting for planets via microlensing Detecting real time microlensing event : OGLE-III and MOA 2 Selecting microlensing event with good planet detection efficiency Two schools : - Mainly high magnification events and alerted anomalies (microFUN) - Monitoring a larger number of events (PLANET/ROBONET). Networks of telescopes to do 24 hours monitoring : PLANET/RoboNET, microFUN Accurate photometry (Image subtraction since 2006) Real time analysis and modeling All data, models, are shared immediately among the microlensing community. Cooperation is the way to go ! OGLE-III has an online anomaly detector (EWS) MOA-II Detecting anomalies real time :

PLANET/ROBONET collaboration : Probing Lensing Anomaly NETwork (current members) M. D. Albrow, J.P. Beaulieu, V. Batista, D. Bennett, D. Bramich, S. Brillant, J. A. R. Caldwell, H. Calitz, A Cassan, K. Cook, C. Coutures, M. Dominik, J. Donatowicz, D. Dominis, P. Fouqué, J. Greenhill, K. Hill, M. Hoffman, N. Kaens, K. Horne, F. Jablonski, U. Jorgensen, S. Kane, D. Kubas, R. Martin, E. Martioli, J. Menzies, P. Meintjes, K. R. Pollard, K. C. Sahu, Y. Tsapras,J. Wambsganss, A. Williams, M. Zub Institut d'Astrophysique de Paris, INSU CNRS, Paris, France Univ. of Canterbury, Dept. of Physics & Astronomy, Christchurch, New Zealand South African Astronomical Observatory, South Africa Boyden Observatory, Bloemfountein, South Africa Canopus observatory, Univ. of Tasmania, Hobart, Australia Niels Bohr Institute, Copenhagen, Denmark Univ. of Potsdam, Potsdam, Germany Space Telescope Science Institute, Baltimore, U.S.A. Perth Observatory, Perth, Australia Boyden 1.5m

PLANET/RoboNet SITES PLANET/RoboNet SITES ESO Danish 1.54m Brazil 0.6m, Sutherland, SAAO 1m Boyden, 1.5m, CCD 2006, 2007 Perth 0.6m Hobart 1m, Robonet : Liverpool 2m, Canary Faulkes North 2m, Hawaii Faulkes South 2m, Australia Goals at each site : - ~1 % photometry, - Adapted Sampling rate - Online analysis. Boyden 1.5m

PLANET DATA PROCESSING At each site : -relative photometry for all stars real time - keep an eye on light curve of prime target Data from all sites are uploaded to Paris (every ~10 min) : Every day, homebase checks : data, light curve fits, BAP, StAndrews priorities algo, Choose strategy, sampling, … Alert the community if anomalies SAAO Boyden Chile Hobart Perth RoboNet

2006 season : 71 events observed by PLANET, 26 by RoboNet 12 events with Amplification > 40 : MOA 99, 137 OGLE 195, 221, 229, 245, 265, 416, 437, 440, events with 40 > Amplification > 10 5 stellar binaries : MOA 3, OGLE 277, 284, 304, Anomalous events : OGLE 38, 109, 207, 215, 238, 375, 398, 435, variable sources : OGLE 357, normal events

CONTRAINTS ON EXTRA SOLAR PLANETS FROM SINGLE LENS Albrow et al., 1998

Detection efficiencies Methods and Models single lens/double lens blending finite source effects Plan (d,q) Plan physique ► Diagrams computed for events Cassan et al. In prep, coming soon… ≈ 70+ diagrams computed so far Combining them in a rigorous way to derive planet abundances.

OGLE-2005-BLG-390 Coopération : PLANET/RoboNET, OGLE-III, MOA-II

AT LAST, A TEXT BOOK MICROLENSING EVENT Data in the anomaly from : PLANET-Danish, OGLE-III, MOA-II, PLANET-Perth Data outside the anomaly from : PLANET/Robonet, PLANET-Hobart Gould Loeb 1992, Bennett & Rhie 1996, …

PROBABILITY DENSITIES OF THE STAR AND ITS PLANET

Detection probabities of a Jupiter or a 5.5 Earth mass In a OGLE-2005-BLG-390 like event

A companion to this frozen super Earth ? Kubas et al., 2007 submitted Excluding at : 50 % Jupiter over AU 70 % 3 Jupiter over AU Core accretion models by Idal & Lin

Neptunes and super-Earth are much more common than Jupiters Same direction as the core accretion model predictions. Beaulieu et al., 2006 Cassan, Kubas, Beaulieu et al., 2007 in prep Gould et al., 2006 Udalski et al., 2005 Bond et al., 2004 PLANET detection efficiencies

(Courtesy K. Horne) DUNE-ML

OGLE-III, MOA-II and PLANET/ROBONET, MicroFUN - Network of telescopes, round the clock monitoring. - Frozen Super Earth are detectable from the ground by microlensing. - Much more common than gazeous giants. - Total cooperation between all teams. Coming out soon : Fractions from Jupiter to super Earth (combining data) Microlensing : Constraints on frozen super Earth. Microlensing : EARTH HUNTER, DUNE-ML, MPF, … Talk by Scott Gaudi (Future microlensing projects) Current status of microlensing planet hunting

OGLE-2005-BLG-071 M* ~ 0.45 Mo 5.2 ± 1.8 kpc 2.7 MJupiter a ~ 2.2 AU or3.7 AU Close binary : d=0.758 q= Wide binary : d=1.294 q= Led by OGLE & microFUN

Central caustic, Degeneracy d 1/d

Earth mass planet signal is washed out for giant source stars Need to monitor small stars to get low mass planets ! Sensitivity to Earths Depends on Source Size

Ground-based confusion, space-based resolution Main Sequence stars are not resolved from the ground Systematic photometry errors for unresolved main sequence stars cannot be overcome with deeper exposures (i.e. a large ground- based telescope). High Resolution + large field + 24hr duty cycle

2007 should be fun ! HOLMES Hunting fOr Low Mass Extrasolar Planets Funded by Agence Nationale de la Recherche, France ( )