Planets & Brown Dwarf Companions

Transcription

1 Planets & Brown Dwarf Companions High contrast and High Angular Resolution Imaging Gaël Chauvin Gaël Chauvin, David Mouillet & Jean-Luc Beuzit LAOG-CNRS, Grenoble Observatory, France (LAOG Grenoble Observatory) Spirit of Lyot Conference, Berkeley, June 2007 Outline I- Brief introduction First discoveries (Gl299B, 51 Peg b). Development of new observing techniques. Advantage of direct imaging to explore the AU missing link. II- Observing challenge & technical needs Faint companion close to bright stars. Observing Limitations. Technical needs: AO, Coronography, Differential Imaging... III- Target selection & main surveys Targets identification and selection: distance and age. Young, nearby stars. Intermediate-old stars, Very, nearby stars and Exoplanet hosts Summary of the main surveys: observing technique, sample size and performances IV- Observing strategy & main results 1) Deep imaging, 2) Astrometry and 3) Photometry + Spectroscopy Access to planetary masses. Physical and chemical properties. Origin of formation Typical detection limits and statistical analysis VI- Conclusion & perspectives Spirit of Lyot Conference, Berkeley, June

2 First Brown Dwarf Discovery Brown Dwarf: predicted to be not massive enough to start Hydrogen-burning ( 1962 (Kumar Mass < 75 M Jup Brief Introduction ( 1995 al. : First brown dwarf, companion to Gliese 229 (Nakajima et 1995 Adaptive optics + coronography, Palomar Observatory Gl 229 A d = 5.7 pc Age ~0.5 Gyr M A = 0.5 M Sun Gl 229 B T eff = 900 K M B =25 M Jup Sep = 45 UA Important Population of Brown Dwarfs : Beginning of large surveys in optical (SDSS) and nir (2MASS, DENIS) Hundreds of isolated brown dwarfs in the field (+600) ~10 Brown dwarf companions detected at large separations > 1000 AU Brief Introduction Detection of the companion Epsilon Indi B (brown dwarf binary Ba & Bb) Epsilon Indi A & Bab d = 3.6 pc Age = Gyr M Ba = 50 M Jup M Bb = 40 M Jup Sep = 1460 UA ( 2003 al. (Scholz et 2

3 New Spectral Classification : New spectral classification beyond late-m dwarfs - L Dwarfs ( K): atmosphere saturated with dust, extremely red colors. (optical) absence of TiO and VO - absorption of H 2 O - T Dwarfs ( K): dust condensation or rain-out in the atmosphere, bluer, near-ir spectra: absorption of H 2 O and CH 4 Brief Introduction M D w a r f s L D w a r f s S t a r s M > 7 5 M J u p B D s 1 3 < M < 7 5 M J u p E G P s M < 1 3 M J u p T D w a r f s ( 2001 al. (Burrows et Discovery of the First Exo-planet 1995 : Radial velocity measurements, 1st Exo-planet orbiting 51 Peg Minimum mass of M 2 sini > 0.45 M Jup and a period P = 4.23 days ( 1995 (Mayor & Queloz Brief Introduction 3

4 Large Diversity of Planetary Systems 1995 : Radial velocity measurements, 1st Exo-planet orbiting 51 Peg Minimum mass of M 2 sini > 0.45 M Jup and a period P = 4.23 days ( 1995 (Mayor & Queloz Brief Introduction Nowadays, > G. M a r c y ' s R e v i e w - The most successful technique! - More than 200 Exo-planets discovered ( - Brown dwarf desert at short separations < 4 AU ( sini - High diversity of masses, orbital parameters (P, a, e, M 2 Period Mass Eccentricity Distributions - RV precision allows access to telluric masses - Host Stars Studies: Impact of Metallicity Multiplicity Age > X. B o n fi l s ' s T a l k > M. M u g r a u e r ' s T a l k a n d T. S c h m i d t ' s P o s t e r Planets (& BDs) hunting techniques Radial Velocity Pulsar Timing ( m1 m2 sini (hyp. P, e, a, ω, T 0 ( m1 m2 sini (hyp. P, e, a, ω, T 0 I n d i r e c t Brief Introduction Gravitational Micro-lensing Photometric Transit (Secondary Eclipse) Classical, HC & HAR Imaging d m2, m1, ( event P, a (single (* R*-M R2, R1, m1 (e=0; P, a, i, T 0 m1, m2 P, a, e, i, ω, T 0 d i r e c t > Spectroscopic Characterization of Planet and BD atmopsheres ( TPF/Darwin + Astrometric Wobbling (VLTI/PRIMA, GAIA), Interferometry (SIM, 4

5 Missing Link between 5 and 500 AU ( AU ) K u i p e r O o r t C l o u d - S o l a r S y s t e m - C i r c u m s t e l l a r D i s k s Brief Introduction RV, Transit, ( AU Micro-lensing (< 5 Large surveys ( AU (> M u l t i p l i c i t y > 200 exo-planets Brown dwarf desert ~10 brown dwarf companions 2MASS and DENIS Missing Link between 5 and 500 AU ( AU ) K u i p e r O o r t C l o u d - S o l a r S y s t e m - C i r c u m s t e l l a r D i s k s Brief Introduction High Contrast/High Angular Resolution Direct Imaging - M u l t i p l i c i t y R a p i d c o n fi r m a t i o n ( 1-2 y r s ) S p e c t r a l c h a r a c t e r i z a t i o n S t u d y o f o r b i t a l p a r a m e t e r s ) e P h y s i c o - c h e m i s t r y ( S t r u c t u r e & a t m o s p h e r ( HST/NICMOS ) TWA5 B ( 1999 al. (Lowrance et O r i g i n o f f o r m a t i o n 5

6 Outline I- Brief introduction First discoveries (Gl299B, 51 Peg b). Development of new observing techniques. Advantage of direct imaging to explore the AU missing link. II- Observing challenge & technical needs Faint companion close to bright stars. Observing Limitations. Technical needs: AO, Coronography, Differential Imaging... III- Target selection & main surveys Targets identification and selection: distance and age. Young, nearby stars. Intermediate-old stars, Very, nearby stars and Exoplanet hosts Summary of the main surveys: observing technique, sample size and performances IV- Observing strategy & main results 1) Deep imaging, 2) Astrometry and 3) Photometry + Spectroscopy Access to planetary masses. Physical and chemical properties. Origin of formation Typical detection limits and statistical analysis VI- Conclusion & perspectives Spirit of Lyot Conference, Berkeley, June 2007 Observing Challenge D e t e c t / c h a r a c t e r i z e s o m e t h i n g f a i n t, s p a t i a l l y c l o s e t o s o m e t h i n g b r i g h t Observing Challenge and Technical Needs - Relative flux (photometry) Emitted light of the companion Luminosity vs model predictions (Mass, luminosity, Teff...) ( astrometry ) - Relative position (? comoving ) proper motion (? companion orbital motion (Bound - Spectral information (spectroscopy) Atmosphere characterization Molecules, Dust properties Gravity, Effective Temperature 6

7 Technical Needs D e t e c t / c h a r a c t e r i z e s o m e t h i n g f a i n t, s p a t i a l l y c l o s e t o s o m e t h i n g b r i g h t Observing Challenge and Technical Needs - High image quality High angular resolution PSF Stability Calibration of statical aberrations - PSF Halo Brightness Halo attenuation? Inner working angle? Speckle-noise Photon-noise - Intrinsic companion faintness C. M a r o i s, R. S o u m m e r ' s T a l k s Long overall observations Background/Readout-noise limits Technical Needs ) r L a r g e t e l e s c o p e s, w i t h A O s y s t e m f r o m t h e g r o u n d ( > L i s a P o y n e e Observing Challenge and Technical Needs Handling instrumental artefacts: design, active correction, calibration I m p r e s s i v e E v o l u t i o n G Q l u p ESO3.6m/Come-On VLT/NACO 2005 ( 2007 al. (Janson et (Neuhäuser et al 05) 7

8 Technical Needs L a r g e t e l e s c o p e s, w i t h A O s y s t e m f r o m t h e g r o u n d Observing Challenge and Technical Needs Handling instrumental artefacts: design, active correction, calibration Coronography - Occulting Mask Saturated Imaging - Lyot Coronography Technical Needs L a r g e t e l e s c o p e s, w i t h A O s y s t e m f r o m t h e g r o u n d Observing Challenge and Technical Needs Handling instrumental artefacts: design, active correction, calibration Coronography D e t e c t i o n L i m i t s : H - b a n d O b s. T i m e ~ 1 0 m i n S t a r, H = 5-6 ( d = 5 0 p c ) 8

9 Technical Needs L a r g e t e l e s c o p e s, w i t h A O s y s t e m f r o m t h e g r o u n d Observing Challenge and Technical Needs Handling instrumental artefacts: design, active correction, calibration Coronography Differential techniques: ADI, SDI, Polarimetry H S T r o l l a n g l e ( L o w r a n c e e t a l. 9 9 ; 0 0 ; 0 5 ) B e i n g r e v i s i t e d / o p t i m i z e d, f o r o b s. p r o c e d u r e s a n d d a t a a n a l y s i s ( M a r o i s e t a l ) D e t a i l s d e p e n d e n t o n t e l e s c o p e, F o c u s, d e f e c t s o r i g i n a n d s t r u c t u r e > C. M a r o i s ' s T a l k > J. F a r i h i a n d D. L a f r e n i è r e T a l k s Technical Needs L a r g e t e l e s c o p e s, w i t h A O s y s t e m f r o m t h e g r o u n d Observing Challenge and Technical Needs Handling instrumental artefacts: design, active correction, calibration Coronography Differential techniques: ADI, SDI, Polarimetry M e t h a n e - r i c h c o m p a n i o n, T 2 - T 8 B D s S D I C o n c e p t : C F H T / T R I D E N T ( R a c i n e e t a l ; M a r o i s e t a l ) R e s u l t s : ( M c C a u g h r e a n e t a l ; C l o s e e t a l ; B i l l e r e t a l ) > B. B i l l e r ' s T a l k > G. M o n t a g n i e r ' s T a l k 9

10 Outline I- Brief introduction First discoveries (Gl299B, 51 Peg b). Development of new observing techniques. Advantage of direct imaging to explore the AU missing link. II- Observing challenge & technical needs Faint companion close to bright stars. Observing Limitations. Technical needs: AO, Coronography, Differential Imaging... III- Target selection & main surveys Targets identification and selection: distance and age. Young, nearby stars. Intermediate-old stars, Very, nearby stars and Exoplanet hosts Summary of the main surveys: observing technique, sample size and performances IV- Observing strategy & main results 1) Deep imaging, 2) Astrometry and 3) Photometry + Spectroscopy Access to planetary masses. Physical and chemical properties. Origin of formation Typical detection limits and statistical analysis VI- Conclusion & perspectives Spirit of Lyot Conference, Berkeley, June 2007 Target Selection: Stars near the Sun Target Selection & Main HAR and HC imaging Surveys D i s t a n c e < p c 10

11 Target Selection: Age Target Selection & Main HAR and HC imaging Surveys S t a r s M > 7 5 M J u p B D s 1 3 < M < 7 5 M J u p E G P s M < 1 3 M J u p ( 2001 al. (Burrows et 1) Young, nearby Associations Target Selection & Main HAR and HC imaging Surveys A g e ( < M y r ) ) c D i s t a n c e ( < p ( TW Hya, an isolated T Tauri star (Rucinski & Krautter - ( 1997 al Identification of 5 first members of the TWA Association (Kastner et - - Now. 5 associations: TWA, β Pictoris, AB Dor,Tucana/Horologium & η Chameleontis + New stars from the SACY survey Identification Groups: stars > Total of young, nearby (AFGKM) Zuckerman, Song et al.; Torres, de la Reza et al. Mamajek et al.; Ortega et al.; ByN et al. Age & membership diagonostic - Abnormal colors, luminosity Optical/nIR photometry - Rotation & Stellar Activity Optical Spectroscopy: SpT, Hα, Li - Li Abundance X-ray Activity - Stellar Kinematics RV and proper motions 11

12 1) Young, nearby Associations Target Selection & Main HAR and HC imaging Surveys A g e ( < M y r ) ) c D i s t a n c e ( < p T y p i c a l d e t e c t i o n l i m i t s : M B > 1 M j u p a t p h y s i c a l s e p a r a t i o n s > A U T o s e a r c h f o r a n d t o c h a r a c t e r i z e p l a n e t a r y m a s s c o m p a n i o n s - HST/NICMOS Corono 45 ( 2005 (1999, 2000, al. Lowrance et - Keck/NIRC AO-Corono - MacIntosh et al. (01); Kaisler et al. (01) ( 2003 (2002, al. - ESO3.6m/ADONIS AO-Corono 29 Chauvin et ( 2005 (2003, al. - NTT3.5m/Sharp Saturated 32 Neuhäuser et - VLT/NACO AO-Saturated 28 Masciadri et al. (2005) ( 2007 ) al. - VLT/NACO AO-Lp 22 Kasper et ( 2005 ) al. - VLT & MMT AO-SDI 45 Biller et al. (2007), Close et > Beth Biller's Talk T W A 5 B H R B G S C B A B P i c B ( L o w r a n c e e t a l ) ( L o w r a n c e e t a l ) ( C h a u v i n e t a l ) ( C h a u v i n e t a l ) 1) Young, nearby Associations Target Selection & Main HAR and HC imaging Surveys A g e ( < M y r ) ) c D i s t a n c e ( < p T y p i c a l d e t e c t i o n l i m i t s : M B > 1 M j u p a t p h y s i c a l s e p a r a t i o n s > A U T o s e a r c h f o r a n d t o c h a r a c t e r i z e p l a n e t a r y m a s s c o m p a n i o n s - HST/NICMOS Corono 45 ( 2005 (1999, 2000, al. Lowrance et - Keck/NIRC AO-Corono - MacIntosh et al. (01); Kaisler et al. (01) ( 2003 (2002, al. - ESO3.6m/ADONIS AO-Corono 29 Chauvin et ( 2005 (2003, al. - NTT3.5m/Sharp Saturated 32 Neuhäuser et - VLT/NACO AO-Saturated 28 Masciadri et al. (2005) ( 2007 ) al. - VLT/NACO AO-Lp 22 Kasper et ( 2005 ) al. - VLT & MMT AO-SDI 45 Biller et al. (2007), Close et and more results to come > Beth Biller's Talk - HST/NICMOS Corono 109 > Jay Farihi's Talk - Gemini/GPDS AO-ADI 85 > David Lafreniere's Talk - VLT/NACO AO-Corono - Melo et al.; Chauvin et al. - Gemini/NICI AO-Corono - Liu et al. 12

13 2) Intermediate-old Stars Target Selection & Main HAR and HC imaging Surveys A g e ( G y r ) D i s t a n c e ( < p c ) T y p i c a l d e t e c t i o n l i m i t s : M > 1 0 M ( > A U ) B j u p B D c o m p a n i o n s t u d y : E x t e n s i o n o f t h e B D d e s e r t a t i n t e r m e d i a t e s e p a r a t i o n s? - Gemini/Hokupa'a Classical 31 Potter et al. ( 2002 ) - Keck/NIRC AO-Corono 102 McCarthy & Zuckerman ( 2004 ) Lick/GEMINI AO-Corono Palomar PALAO AO-Corono 101 Metchev et al. (2005, ( 2006 KeckII/NIRC2 - Spitzer Classical-midIR 73 Luhman et al. ( 2006 ) H D B C H D B H D B H N P e g B ( P o t t e r e t a l ) ( M e t c h e v e t a l ) ( M e t c h e v e t a l ) ( L u h m a n e t a l ) 3) Very Nearby Stars Target Selection & Main HAR and HC imaging Surveys A g e ( G y r ) D i s t a n c e ( < p c ) T y p i c a l d e t e c t i o n l i m i t s : M > 2 0 M ( 1 G y r ) a n d M > 6 0 M ( 1 0 G y r ) a t ( > A U ) B j u p B j u p B D c o m p a n i o n s t u d y : E x t e n s i o n o f t h e B D d e s e r t a t i n t e r m e d i a t e s e p a r a t i o n s? > V o l u m e - l i m i t e d s a m p l e o f A F G K M s t a r s - Palomar/AOC AO-Corono 24 (<10 pc) Nakajima et al. ( 1994 ) - HST/WFPC Classical 13 (<13 pc) Schroeder et al. ( 2000 ) - Palomar (60i, 200i) AO-Corono 107 (<8 pc) Oppenheimer et al. ( 2001 ) - Palomar PALAO AO-Corono 80 (<22 pc) Carson et al. (2005, ( Palomar PALAO AO-Corono EPIcS sample > A. Tanner's Talk H R B ( L i u e t a l ) G l B ( N a k a j i m a e t a l ) 13

14 3) Very Nearby Stars Target Selection & Main HAR and HC imaging Surveys A g e ( G y r ) D i s t a n c e ( < p c ) T y p i c a l d e t e c t i o n l i m i t s : M > 2 0 M ( 1 G y r ) a n d M > 6 0 M ( 1 0 G y r ) a t ( > A U ) B j u p B j u p B D c o m p a n i o n s t u d y : E x t e n s i o n o f t h e B D d e s e r t a t i n t e r m e d i a t e s e p a r a t i o n s? > V o l u m e - l i m i t e d s a m p l e o f A F G K M s t a r s > F o c u s e d o n M s t a r s - Gemini/Hokupa'a AO-Classical 39 Close et al. (2002, 2003) - VLT/Gemini/Subaru AO-Classical 36 (<30 pc) Siegler et al., (2003, 2005) - CFHT/PUE'O AO-Classical (<12 pc) Beuzit et al. ( 2004 ) - Gemini/Altair-NIRI AO-Saturated 41 (<20pc) Daemgen et al. ( 2007 ) - VLT/NACO AO-Classical Biller et al. (2006); Montagnier et al. ( 2006 ) S C R B ( B i l l e r e t a l ) 3) Very Nearby Stars Target Selection & Main HAR and HC imaging Surveys A g e ( G y r ) D i s t a n c e ( < p c ) T y p i c a l d e t e c t i o n l i m i t s : M > 2 0 M ( 1 G y r ) a n d M > 6 0 M ( 1 0 G y r ) a t ( > A U ) B j u p B j u p B D c o m p a n i o n s t u d y : E x t e n s i o n o f t h e B D d e s e r t a t i n t e r m e d i a t e s e p a r a t i o n s? > V o l u m e - l i m i t e d s a m p l e o f A F G K M s t a r s > F o c u s e d o n M s t a r s - Gemini/Hokupa'a AO-Classical 39 Close et al. (2002, 2003) - VLT/Gemini/Subaru AO-Classical 36 (<30 pc) Siegler et al., (2003, 2005) - CFHT/PUE'O AO-Classical (<12 pc) Beuzit et al. ( 2004 ) - Gemini/Altair-NIRI AO-Saturated 41 (<20pc) Daemgen et al. ( 2007 ) - VLT/NACO AO-Classical Biller et al. (2006); Montagnier et al. ( 2006 ) > L and T dwarfs multiplicity studies Bouy et al. (2003); Gizis et al. ( 2003 ) Reid et al. (03): Burgasser et al. ( 2003 ) 14

15 4) Stars with RV planets & RV drifts Target Selection & Main HAR and HC imaging Surveys A g e ( G y r ) ) c D i s t a n c e ( < 5 0 p T y p i c a l d e t e c t i o n l i m i t s : M > 2 0 M ( 1 G y r ) a n d M > 6 0 M ( 1 0 G y r ) a t ( > B j u p B j u p ) U A > Stars with RV planets M a s s i v e c o m p a n i o n s a t l o n g - p e r i o d s? D y n a m i c a l i m p a c t o n i n n e r p l a n e t a r y s y s t e m s? - KeckII/kCam AO-Saturated 25 ( 2002 ) Luhman & Jayawardhana - NTT/Sofi Classical-Saturated - ( 2007 (2004, 2006, al. Mugrauer et - VLT/NACO AO-Corono 26 Chauvin et al. (2006, 2007) - VLT/NACO AO-Classical 103 ( 2007 ) al. Eggenberger et - Spitzer Classical-midIR 48 ( 2006 ) al. Luhman et > Stars with long RV trends - VLT/NACO AO-SDI > G. M o n t a g n i e r ' s T a l k Target Selection & Main HAR and HC imaging Surveys Star Forming Regions (1-120 Myr and >100 pc) Chameleon, Pleiades, Taurus substellar IMF Studies VLM multiplicity > A. Tanner's Talk Young Brown dwarfs Favorable Contrast IR-AO, LGS-AO > L. Close's Talk White dwarfs ( 1988 GD 165 B (Becklin & Zuckerman Fossil of planetary system? and more... D H T a u B ( I t o h e t a l ) 2 M B ( C h a u v i n e t a l ) G Q L u p B ( N e u h ä u s e r e t a l ) C H X R 7 3 B ( L u h m a n e t a l ) 15

16 Outline I- Brief introduction First discoveries (Gl299B, 51 Peg b). Development of new observing techniques. Advantage of direct imaging to explore the AU missing link. II- Observing challenge & technical needs Faint companion close to bright stars. Observing Limitations. Technical needs: AO, Coronography, Differential Imaging... III- Target selection & main surveys Targets identification and selection: distance and age. Young, nearby stars. Intermediate-old stars, Very, nearby stars and Exoplanet hosts Summary of the main surveys: observing technique, sample size and performances IV- Observing strategy & main results 1) Deep imaging, 2) Astrometry and 3) Photometry + Spectroscopy Access to planetary masses. Physical and chemical properties. Origin of formation Typical detection limits and statistical analysis VI- Conclusion & perspectives Spirit of Lyot Conference, Berkeley, June 2007 I/3- Systematic Search for Faint Objects NACO/VLT, Ks + S27 (27 mas/pix), FoV 28'' 28'' Classical and coronographic (Ø = 0.7 et Ø = 1.4 ) imaging Observing Time / source ~ 1 hr AB Pic 16

17 2/3- Astrometric Follow-up Observations Background object or physical companion? Proper motion study of AB Pic b AB Pic A: - Proper motion - Parallactic Motion Follow-up at several epochs 3/3- Photometric & Spectroscopic Characterization Photometry versus predictions evolutionary models a Identification of atomic and molecular lines: H 2 0, CO, CH 4, FeH, NaI, CaI, KI Confirmation of a cool atmosphere H 2 O NaI AB Pic B ( L1 ) 2M CO H 2 O AB Pic B M ~ M jup et Sep = 260 AU Spectral Type ~L1!! Gliese 86 B case!! same nir L/colors for BD or WD 17

18 Results: Substellar companions of nearby stars TWA5 B HR7329 B GSC8048 B DHTau B GQ Lup B CHXR73 B Gl229 B G B - GGTau B HD BC HD49197 B Gl577 BC HR7672 B 2M1207 B - G l D - G J C - ε I n d i B a b AB Pic B HD B SCR1845 B HNPeg B HD3651 B - GJ1001 BC - G J C D AO, HST - Gl569 Bab - Gl1048 B - G l B C Large Surveys, Classical Imaging Spitzer Results: Physical and Chemical Properties Thermal Emission: L (Teff & R) ( Formation Mass, Age, composition (& Companions, thanks to the primary: > known distance Hipparcos Parallax Moving Cluster Method > known metallicity Primary optical spectroscopy > relatively well known age: age of the young, nearby association Photometry vs evol. models Stellar kinematics, Dust lumikosity Li abundance, Stellar rotation Stellar activity: X-ray, Hα, emission lines 18

19 Results: Physical and Chemical Properties nir photometry d, a g e L, T eff, R, M Evolutionary Interior Models > Internal structure (Teff, L, mass, radius) Tucson: (Burrows et al. 1997; ( 1999 NASA-Ames: Marley et al. ( 2007 ) Lyon: (Chabrier et al. 2000, Baraffe et al. 1998, ( 2003 Synthetic spectra of Atmospheric Models > Molecular, dust opacities. Dust formation/condensation > Boundary conditions on interior calculations Tucson: Burrow et al. (2001; 2002; ( 2006 NASA-Ames: Marley et al. (1999; ( 2002 Lyon: Allard et al. (2001; ( 2003 Results: Physical and Chemical Properties d nir photometry L a g e T eff, R, M nir spectroscopy Young / Old M, L dwarfs: AB Pic B (10-20 M jup ; 260 ( AU Spectral Type ~L1 (Song et al. ( 2006 Spectral Type (Old field BDs) Spectral indexes (H2O, CO, ( CH4 Bolometric corrections Evol. Interior Models 2MASS 0141; L0-L2 (Kirkpatrick et al. ( 06 19

20 Results: Physical and Chemical Properties d nir photometry L a g e T eff, R, M nir spectroscopy d Spectral Type (Old field BDs) Spectral indexes (H2O, CO, ( CH4 Bolometric corrections log(g), Teff R, M, L, age Synthetic spectra of substellar atmospheres > Molecular, dust opacities. Dust Formation/condensation > Boundary conditions on interior calculations Tucson: Burrow et al. (2001; 2002; ( 2006 NASA-Ames: Marley et al. (1999; ( 2002 Lyon: Allard et al. (2001; ( 2003 > K. L u h m a n ' s T a l k Evol. Interior Models Results: Physical and Chemical Properties M. M a r l e y ' s T a l k : > U n c e r t a i n t i e s w i t h E v o l u t i o n a n d A t m o s p h e r i c M o d e l s i n i t i a l C o n d i t i o n s C l o u d M o d e l l i n g C o n v e c t i o n R e m a i n i n g l i n e s F o r m a t i o n m e c h a n i s m s C o m p o s i t i o n M o d e l s : n e e d t o b e c a l i b r a t e d f o r y o u n g ( < M y r ) a g e s a n d v e r y l o w m a s s e s > D y n a m i c a l m a s s e s : E c l i p s i n g B i n a r y, D i s k K i n e m a t i c s, A s t r o m e t r y & S p e c t r o s c o p y D M T a u, C Y T a u ( S i m o n e t a l ) H D A B ( B o d e n e t a l ) T W A 5 A a b ( K o n o p a c k i e t a l ) 2 M A S S A B ( S t a s s u n e t a l ) A B D o r ( C l o s e e t a l. 0 5, 0 7 ; L u h m a n e t a l ) > A. B o c c a l e t t i ' s T a l k 20

21 Results: Physical and Chemical Properties M. M a r l e y ' s T a l k : > U n c e r t a i n t i e s w i t h E v o l u t i o n a n d A t m o s p h e r i c M o d e l s i n i t i a l C o n d i t i o n s C l o u d M o d e l l i n g C o n v e c t i o n R e m a i n i n g l i n e s F o r m a t i o n m e c h a n i s m s C o m p o s i t i o n M o d e l s : n e e d t o b e c a l i b r a t e d f o r y o u n g ( < M y r ) a g e s a n d v e r y l o w m a s s e s > D y n a m i c a l m a s s e s : E c l i p s i n g B i n a r y, D i s k K i n e m a t i c s, A s t r o m e t r y & S p e c t r o s c o p y > H R - r e s o l u t i o n s p e c t r o s c o p y i n o p t i c a l + A t m o s p h e r i c M o d e l s ( M o h a n t y e t a l a, b ) Results: Substellar companions of nearby stars Large Surveys Transits Radial Velocity H C & H A R I m a g i n g µ Lensing 21

22 Results: 2M1207B, First Planetary Mass Companion? M A ~ 24 M Jup Formation scenario? M B ~ 8 M Jup ( 2005 al. 2M1207B, (Chauvin et al. 2005; Lodato et ( 1969 > Opacity limit for fragmentation reached (Larson > Overlap between formation mechanisms ( 1996 al. Core-accretion (Pollack et ( 1997 Disk Instability (Boss ( BDs Collapse/Fragmentation (stars & - M disk > 0.3 M A - T core Accr. > 10 Myr Other substellar companions (HC & HAR imaging): > Mass ratio, wide separation star/bd formation mechanism Soon, some ambiguous cases? Results: Detection Limit Interpretation Y o u n g, N e a r b y S t a r G K s t a r K ~ 7 A g e ~ 1 0 M y r d ~ 3 0 p c E v o l. M o d e l ) 3. 0 l ( B a r a f f e e t a 22

23 Results: Statistical Analysis Detection Limits (minimum mass, projected physical separation) Monte Carlo Simulations ( e Physical properties (mass, a, of EGP and BD companion population Formation mechanisms of BDs & EGPs Results: Statistical Analysis Young (10-30 Myr), nearby stars: Population of EGPs at wide orbits? I n p u t s - Probability Distributions: Semi-major axis P(a) ~ a α [0.3 a max ] AU Eccentricity e = 0; RV distribution a EGP Mass P(m) ~ m -1.5 [1-50] M jup - adjustement with RV surveys (3%, 1-3 AU, > 1 M jup ( 2005 al., Marcy et MC Drawing: Comparison with detection limits & null-detection Probability for an EGP population to be consistent with the survey ( 2007 al. Results: VLT/NACO-Lp (Kasper et Small outer radii (a max < 15 AU) and Decreasing radial distrib. (α<0) MMT-VLT/SDI (Biller et al. 2007) > Poster by E. Nielsen Rule out combination of M, e, constant-a distributions, a max > Observational constraints on the outer part of the planetray systems 23

24 Results: Statistical Analysis Very nearby MS stars: BD desert at intermediate separations? I n p u t s - Set of simulated orbits: a, e, i, ω ( ; al. (Carson et - BD Mass function similar to SFRs MC Drawing: Comparison with detection limits & null-detection Fraction of BD companion Results: BD desert studies revisited for intermediate separations f BD of % for a =[25 100] AU RV: f BD ( 2000 < 1% for a < 3 AU (Marcy & Butler > no significant conclusion about the BD desert extension - Difference in the companion fraction between stellar/bd companions? - Efficiency of the Acretion/ejection BD mechanism (Reipurth & Clarke 2001)? Outline I- Brief introduction First discoveries (Gl299B, 51 Peg b). Development of new observing techniques. Advantage of direct imaging to explore the AU missing link. II- Observing challenge & technical needs Faint companion close to bright stars. Observing Limitations. Technical needs: AO, Coronography, Differential Imaging... III- Target selection & main surveys Targets identification and selection: distance and age. Young, nearby stars. Intermediate-old stars, Very, nearby stars and Exoplanet hosts Summary of the main surveys: observing technique, sample size and performances IV- Observing strategy & main results 1) Deep imaging, 2) Astrometry and 3) Photometry + Spectroscopy Access to planetary masses. Physical and chemical properties. Origin of formation Typical detection limits and statistical analysis VI- Conclusion & perspectives Spirit of Lyot Conference, Berkeley, June

25 Conclusions (... transit - HC and HAR Direct Imaging: - complementary to other techniques (RV, - Spectral characterization, orbit monitoring Conclusions & Perspectives - Missing link between AU - Impressive evolution: - Technique: telescope, AO, observing modes ( associations - Target selection (Young, nearby - Key results: - increasing number of substellar companions since Importance of atmosphere and evolution models - access to planetary mass companions > raising questions related to fomation mechanisms - Interpration of survey detection limits > outer part of planetary systems > constraints for planetary and BD formation scenarii Perspectives - Upcoming: Conclusions & Perspectives NTT/Sofi, HST/NICMOS, GDPS-ADI Gemini/NICI, VLT/NACO SACY survey AEOS/Lyot project - Horizon 2010 Subaru/HiCIAO Gemini Planet Imager VLT/SPHERE > Session (tomorrow): Futur Instruments & Telescopes 25