Searching for Frozen super Earth Searching for Frozen super Earth mass planet via microlensing.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 (2007-2011)

See also contributions by J. Donatowicz (TU Wien), S. Gaudi (Ohio)

1-7 kpc from Sun

Galactic center Sun8 kpc

Light curve

Source starand images

Lens starand planet Observer

Target Field in the Central Galactic BulgeTarget Field in the Central Galactic Bulge

Currently, OGLE-III and MOA-II

UnveilingUnveiling a planetary companion a planetary companion

tp q tE

tE 20 j, M 0.3 Msun :

Jupiter : q 3 10-3 tp 1 j

Terre : q 10 5 tp 1.5 h

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

Earth mass planet signal is washed out for giant source stars

Need to monitor small stars to get low mass planets.Need to monitor small stars to get low mass planets.

1996, sensitivity to Earths depends on source size1996, 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 [(0.6     1.6)RE] is nearly 100%, with the probability remaining high down to Saturn masses and substantial even at 10 Earth masses. »

Detection ≠ characterizationPlanetary 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, microFUNAccurate 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 PLANET/ROBONET collaboration : collaboration :

Probing Lensing Anomaly Probing Lensing Anomaly NETwork (current members)NETwork (current members)

http://planet.iap.fr http://planet.iap.frM. 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, FranceUniv. of Canterbury, Dept. of Physics & Astronomy, Christchurch, New ZealandSouth African Astronomical Observatory, South AfricaBoyden Observatory, Bloemfountein, South AfricaCanopus observatory, Univ. of Tasmania, Hobart, AustraliaNiels Bohr Institute, Copenhagen, DenmarkUniv. of Potsdam, Potsdam, GermanySpace Telescope Science Institute, Baltimore, U.S.A.Perth Observatory, Perth, Australia

Boyden 1.5m

PLANET/RoboNet PLANET/RoboNet SITESSITES

ESO Danish 1.54m 2003-2008Brazil 0.6m, 2007+

Sutherland, SAAO 1m 2002-2007+Boyden, 1.5m, CCD 2006, 2007

Perth 0.6m 2002-2007+Hobart 1m, 2002-2007+Robonet : Liverpool 2m, Canary 2005+Faulkes North 2m, Hawaii 2006+Faulkes South 2m, Australia 2007+

Goals at each site : - ~1 % photometry, - Adapted Sampling rate - Online analysis.

Boyden 1.5m

PLANET DATA PROCESSINGPLANET 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

SAAOBoyden

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, 45117 events with 40 > Amplification > 105 stellar binaries : MOA 3, OGLE 277, 284, 304, 3359 Anomalous events : OGLE 38, 109, 207, 215, 238, 375, 398, 435, 4502 variable sources : OGLE 357, 47452 normal events

CONTRAINTS ON EXTRA SOLAR CONTRAINTS ON EXTRA SOLAR PLANETS FROM PLANETS FROM SINGLE LENSSINGLE LENS

Albrow et al., 1998

Detection efficienciesDetection efficiencies

Methods and Models

• single lens/double lens

• blending

• finite source effects

Plan (d,q)Planphysique

► Diagrams computed for 1995-2005 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-390OGLE-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-PerthData outside the anomaly from : PLANET/Robonet, PLANET-Hobart

Gould Loeb 1992, Bennett & Rhie 1996, …

PROBABILITY DENSITIES OF THE PROBABILITY DENSITIES OF THE STAR AND ITS PLANETSTAR AND ITS PLANET

Detection probabities of a Jupiter or a 5.5 Earth massDetection probabities of a Jupiter or a 5.5 Earth massIn a OGLE-2005-BLG-390 like eventIn a OGLE-2005-BLG-390 like event

A companion to this frozen super Earth ?

Kubas et al., 2007 submittedExcluding at : 50 % Jupiter over 1.1-2.3 AU 70 % 3 Jupiter over 1.5-2.2 AU Core accretion models by Idal & Lin

Neptunes and super-Earth are much more common than JupitersSame 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., 2005Bond 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 1995-2005 data)

Microlensing 2007-2010 : Constraints on frozen super Earth.

Microlensing 2011+ : EARTH HUNTER, DUNE-ML, MPF, …

Talk by Scott Gaudi (Future microlensing projects)

Current status of microlensing planet huntingCurrent status of microlensing planet hunting

OGLE-2005-BLG-071

M* ~ 0.45 Mo5.2 ± 1.8 kpc2.7 MJupitera ~ 2.2 AU or3.7 AU

Close binary : d=0.758q=6.7 10-3

Wide binary :d=1.294q=7.1 10-3

Led by OGLE & microFUN

Central caustic, Degeneracy d 1/d

Earth mass planet signal is washed out for giant source stars

Earth mass planet signal is washed out for giant source stars

Need to monitor small stars to get low mass planets !Need to monitor small stars to get low mass planets !

Sensitivity to Earths Depends on Source SizeSensitivity 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 (2007-2011)