OB390 and the new microlensing planets Christian Coutures Eso Santiago September 2006

Planet searches

Overview Planets search with microlensing PLANET network OGLE 2005-BLG-390Lb and others

In the beginning…

Gravitational Lens

Home gravitational lens

Lens with deflecting angle proportional to 1/u Liebes S., 1969 American Journal of Physics 37, Courtesy Phil Yock, Auckland

Relative proper motion Source-Lens. S Major image Minor image L

Wineglass einstein ring

‘PSPL’ light curveImpact parameter Light Curve

Exotics  Parallax: earth movement  Xallarap: mouvement of the (binary) source  Finite size: impact parameter < Rsource (~1  arcsec)  Binary lens (caustic) Distorsions :

SINGLE LENS WITH FINITE SOURCE EFFECTS 3 source sizes : R S = 0.05, 0.1 and 0.2 R E (t-t 0 )/t E OB

DOUBLE LENS Different trajectoriesVery different light curves ! M1M2 Caustic: locus of source positions where amplification is ∞ (in the plane of the lens)

Wineglass planet

Screen light source Camera Inverse ray shooting, caustics

Close/wide q=M 1 / M 2 =1

Three configurations: - close, intermediate, wide Caustics: - 1 central planetary Séparate regimes (Erdl & Schneider 1993) planetary caustics

Jupiter: d - 1/d 1/30 è Jupiter: dégénérescence q Central Caustic degeneracies

A planetary companion

source star finite size Géante du clump: Turn-off M.S.:

Lensing zone

Detection probability

THE HOLLYWOOD APPROACH “Follow the big stars !” 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. » 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. » Two approaches : Big survey telescope, and network of follow up telescopes (NASA, …) Use existing telescopes, and alerts from surveys (PLANET, GMAN, MPS) - Network of telescopes to do monitoring of on going alerts 24/24. - Online analysis to detect anomalies real time. - Monitoring of Bulge giants (brighter !).

PLANET collaboration : Probing Lensing Anomaly NETwork M. D. Albrow, J.P. Beaulieu, D. Bennett, 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, K. Horne, U. Jorgensen, S. Kane, D. Kubas, R. Martin, J. Menzies, P. Meintjes, K. R. Pollard, K. C. Sahu, J. Wambsganss, A. Williams 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 Probing Lensing Anomaly NETwork ? 32 collaborators, 18 institutes, 10 countries 5 telescopes Coopération with RoboNET ( 3 robotic UK telescopes)

SITES PLANET/RoboNet ESO Danish 1.54m Sutherland, SAAO 1m Boyden, 1.5m, CCD Perth 0.6m Hobart 1m, RoboNet/Liverpool 2m, Canary RoboNet Faulkes North 2m, Hawaii RoboNet/Faulkes South 2m, Australia 2006 ? Goals : - 1 % photometry, - Sampling 1 point/hour- - Online analysis. Boyden 1.5m

Followed Alerts 1993: MACHO (†1999), OGLE, EROS (†2003) 1995: MOA Followed Alerts

PLANET DATA PROCESSING At each site : - Relative photometry for all stars real time -“Planet Plotter”: real time fit & display Data from all sites are uploaded to Paris: Every day, homebase checks : data, light curve fits, BAP, StAndrews priorities algo, Choose strategy, sampling, … Alert the community if anomalies SAAO Boyden ESO LS Hobart Perth RoboNet

First successfull online prediction of anomalous event, rotating binary with parallax. 9 updates of PLANET alert.

time scale 60 days, u0=0.128, mass ratio 0.53, d0=0.718 Rotation parameters : Effective motion ( ), PiE=0.14 Dominik et al., 2006 in preparation

Other planets hunters GMAN (Global Microlensing Alert Network): 1995 – 1999, CTIO 0.9m MPS (Microlensing Planet Search): , 1.9m Mount Stromlo MicroFUN (Microlensing Follow-Up Network): 2003, CTIO 1.3m, CTIO-Yale 1.0m, Wise 1.0m, Palomar 1.5m, MDM 2.4m, LOAO 1.0m + 2 t é lescopes amateur RoboNET: 2004, Faulkes-N 2m, Liverpool 2m, (Faulkes-S 2m) OGLE-III EEWS: 2003

HOW about Planets ?

MB9947 At first sight, it looks like a planet… But it is a binary 

THE PLANET THAT NEVER WAS ? Jupiter at 4 AUs ??? A cool model A variable source ? Investigation on the way

MicroFUN PLANET

THE ZOO OF PLANET DATA ANOMALIES PLANET 1995 — 2005 About 40 high magnification events sensitive to planets Identified planets: 1 (+1) Multiple anomalies: 3 (2 rotating binary lenses, 1 binary- lens/binary-source or triple lens) Finite source, single lens: 4 Caustic passages of finite source: 28 (of which 4 over cusps) -- measurements of proper motion, stellar brightness profile Weak, suspected, unclear anomalies: 27 (this pool harbours potential and likely contains some other jewels)

FINALLY A PLANET DETECTED ! MOA 2003-BLG-53/OGLE 2003-BLG-235 Best fit lens distance = 5.2 kpc 90% c.l. range is kpc Best fit separation = 3.0 AU 90% c.l. range is AU Best fit stellar mass = 0.36 M  90% c.l. range is M  Best fit planet mass = 1.5 M jup 90% c.l. range is M jup If lens star is a 0.6 M  white dwarf Dlens = 6.1 kpc ap = 1.8 AU Mp = 2.5 M jup Bond et al., 2004, ApJ 606, L155

2003: MOA 2003-BLG-53/OGLE 2003-BLG-235 BEST FIT (Bennett et al. 2006): Lens distance = 5.8 kpc Proj. separation = 3.6 AU Stellar mass = 0.63 M sun Planet mass = 2.6 M JUP HST images discard that the lens is a 0.6 M sun white dwarf Bond et al., 2004, ApJ 606, L155

2005 (1): OGLE 2005-BLG-071 Two models: close binary : d=0.758 q= wide binary : d=1.294 q= M * ~ 0.13 M sun D OL = 2.9 ± 1.2 kpc 0.9 M JUP a ~ 2.3 AU P ~ 10 yr Wide slightly favoured:

OGLE Field HST Image E N 1” Subo Dong ©

2005 (2): OGLE 2005-BL53G-390

390 story (1) OGLE alerts on july 11, 2005 PLANET observes from july 25

390 story(2) Maximum on july 31st : A = 2.9

390 story(3) another boring event …

390 story(4) Should we drop it?

390 story(5) ? August 10

390 story(6)  ???

390 story(7) Aug. 11th, OGLE confirms !

390 story(8) Yes !

390 story(9) Yessssssssss ! indeed

390 story(10) YESSSSSSSSSS!

A planet ? A binary lens ? A bump in the night…

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

Data in the anomaly from : PLANET-D154, OGLE, MOA-II, PLANET-Perth Data outside the anomaly from : PLANET/Robonet, PLANET-Hobart (Gould & Loeb 1992, Bennett & Rhie 1996) A TEXTBOOK MICROLENSING EVENT

PROBABILITY DENSITIES OF THE STAR AND ITS PLANET

Final Parameters Source distance D S = 1.05 ± 0.25 R GC (R GC =7.62 ± 0.32 kpc) Source star: a Galactic Bulge giant G4 III, R S = 9.6 ± 1.3 R SUN Primary lens mass: Primary lens distance: D L = 6.6 ± 1.0 kpc Planet mass: Planet separation: Orbital period:

Planet temperature and radius Star properties(MS): Planet properties: Model L é ger et al. (2004):

Detecting the lens 390L

contrast: ~4000 en J 5 ans? 35 mas

2005 (3): OGLE 2005-BLG-169 New planet of 13 Earth masses detected by microFUN et OGLE in a very high amplification event (800, i.e. 7.3 mag) Source is a dwarf, moving ~ 8.6 mas/year Close-wide ambiguity (central caustic).

Comparaison fit PSPL et ESBL

Comparing the 4 planets (1) Event qb caustic Max Amp. source OB03235 = KB unique7.6MS OB05071 close central44MS OB05071 wide unique d w = MS OB05169 close unique d c = MS OB05169 wide unique d w = MS OB planétary2.9RG

Comparing the 4 planets (2) t E days u0REu0RE  *  as  E mas  mas yr -1 D L kpc M * M sun M p M earth a AU K m s -1 OB OB05071 wide OB05169 wide OB

Summary Exoplanets

The core accretion model

Events caracteristic times Do giant planets prefer long lasting events (i.e. more massive lenses)?

PLANET detection efficiency

2006 Season May1 - Aug.31 : 7 telescopes 96 alerts followed 12 high amplification, 16 medium (10-40) 5 stellar binairies, 9 anomalous 2 with variable source 52 « PSPL » Promising events: 207, 238, 245, 265 OGLE 2006-BLG-245: The planetary model has

2006 (1): OGLE 2006-BLG-245

Conclusion(s) µlensing still explores ranges complementary to other methods (R.V.) It is able to find light planets around AU Much less easy than it looked: Detection ≠ Caracterization Photometry, sampling, fitting model(s), ambiguities 4 detections with caracterisation 3 central caustics: 2 with high amplification, 1 with low amplification 1 planetary caustic, with low amplification => High Amp events does not work: no simple single strategy! 2 Jupiters, 1 x 13.Earth, 1 x 5.Earth: Good indication that little planets may be more common than gaz giants around M stars (30% vs 0.6%). This confirms the core accretion model. 3 long events, 1 short: Giant planets may be more common around bigger mass stars Imprecision on the star-planet parameters: Better to wait and try to detect the lens …

END

Finding the source size Fitting the curve: We can estimate the apparentangular radius of the source star from measured derredened mags and colours of the source in a CMD: Using the red giant clump in the CMD: position calibrated with the local red giant from Hipparcos: Transform for the distance from the clump, as a function of (l,b) because of the Galactic bar: