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 5-500 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

1 First Brown Dwarf Discovery

Brown Dwarf: “predicted to be not massive enough to start Hydrogen-burning” (Kumar 1962)‏

Mass < 75 MJup

1995 : First brown dwarf, companion to Gliese 229 (Nakajima et al. 1995)‏ Adaptive optics + coronography, Palomar Observatory

Gl 229 A d = 5.7 pc Age ~0.5 Gyr Brief Introduction Brief MA = 0.5 MSun

Gl 229 B

Teff = 900 K

MB=25 MJup Sep = 45 UA

Important Population of Brown Dwarfs

1996-1997: 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

Detection of the companion Epsilon Indi B (brown dwarf binary Ba & Bb)

Epsilon Indi A & Bab d = 3.6 pc Age = 0.8 - 2 Gyr

Brief Introduction Brief MBa = 50 MJup

MBb = 40 MJup Sep = 1460 UA

(Scholz et al. 2003)‏

2 New Spectral Classification

1997-2002 : New spectral classification beyond late-M dwarfs - L Dwarfs (1300-2200K): atmosphere saturated with dust, extremely red colors.

(optical) absence of TiO and VO - absorption of H2O - T Dwarfs (500-1300K): dust condensation or rain-out in the atmosphere, bluer,

near-IR spectra: absorption of H2O and CH4

M D w a r f s Stars M > 75 M Jup

B D s 13 < M < 75 M Jup

EGPs M < 13 M Jup Brief Introduction Brief

L D w a r f s

T D w a r f s

(Burrows et al. 2001)‏

Discovery of the First Exo-planet

•1995 : Radial velocity measurements, 1st Exo-planet orbiting 51 Peg (Mayor & Queloz 1995)‏

Minimum mass of M2sini > 0.45 MJup and a period P = 4.23 days Brief Introduction Brief

3 Large Diversity of Planetary Systems

•1995 : Radial velocity measurements, 1st Exo-planet orbiting 51 Peg (Mayor & Queloz 1995)‏

Minimum mass of M2sini > 0.45 MJup and a period P = 4.23 days

Nowadays, > G . M arcy's Review

• - The most successful technique!

• - More than 200 Exo-planets discovered (www.exoplanets.org)

• - Brown dwarf desert at short separations < 4 AU

• - High diversity of masses, orbital parameters (P, a, e, M2sini)‏ Brief Introduction Brief •Period – Mass – Eccentricity Distributions - RV precision allows access to telluric masses

> X. Bonﬁls's Talk - Host Stars Studies: Impact of Metallicity

Multiplicity > M . M ugrauer's Talk and T. Schm idt's Poster Age

Planets (& BDs) hunting techniques

Radial Velocity m2 sini (hyp. m1)‏ P, e, a, ω, T0

Pulsar Timing m2 sini (hyp. m1)‏

I n d i r e c t P, e, a, ω, T0

Gravitational Micro-lensing m2, m1, d‏ P, a (single event)‏

Photometric Transit R2, R1, m1 (e=0; R*-M*)‏

Brief Introduction Brief (Secondary Eclipse) P, a, i, T0

m1, m2 d i r e c t Classical, HC & HAR Imaging P, a, e, i, ω, T0

> Spectroscopic Characterization of Planet and BD atmopsheres

+ Astrometric Wobbling (VLTI/PRIMA, GAIA), Interferometry (SIM, TPF/Darwin)‏

4 Missing Link between 5 and 500 AU

0 50 100 1000 1000 (AU)‏ . .... K u i p e r O o r t C l o u d ... - Solar System

- C ircum stellar D isks

- M u ltip licity

RV, Transit, Large surveys Brief Introduction Brief Micro-lensing (< 5 AU)‏ (> 500 AU)‏

> 200 exo-planets ~10 brown dwarf companions Brown dwarf desert 2MASS and DENIS

Missing Link between 5 and 500 AU

0 50 100 1000 1000 (AU)‏ . .... K u i p e r O o r t C l o u d ... - Solar System

- C ircum stellar D isks

- M u ltip licity

High Contrast/High Angular Resolution Direct Imaging Brief Introduction Brief

Rapid conﬁrm ation (1-2 yrs)

Spectral characterization

Study of orbital param eters

Physico-chem istry (Structure & atm osphere) ‏

TWA5 B (HST/NICMOS)‏ O rigin of form ation (Lowrance et al. 1999)‏

5 Outline

I- Brief introduction First discoveries (Gl299B, 51 Peg b). Development of new observing techniques. Advantage of direct imaging to explore the 5-500 AU missing link.

II- Observing challenge & technical needs Faint companion close to bright stars. Observing Limitations. Technical needs: AO, Coronography, Differential Imaging...

VI- Conclusion & perspectives

Spirit of Lyot Conference, Berkeley, June 2007

Observing Challenge

D etect/characterize som ething faint, spatially close to som ething bright

- Relative flux (photometry)

Emitted light of the companion Luminosity vs model predictions (Mass, luminosity, Teff...)

- Relative position (astrometry)‏

proper motion (comoving?)‏ orbital motion (Bound companion?)‏

- Spectral information (spectroscopy)

Observing Challenge and Technical Needs Technical and Challenge Observing Atmosphere characterization Molecules, Dust properties Gravity, Effective Temperature

6 Technical Needs

D etect/characterize som ething faint, spatially close to som ething bright

- High image quality

High angular resolution PSF Stability Calibration of statical aberrations

- PSF Halo Brightness

Halo attenuation? Inner working angle?

Speckle-noise C. M arois, R. Soum m er's Talks Photon-noise

- Intrinsic companion faintness Observing Challenge and Technical Needs Technical and Challenge Observing

Long overall observations Background/Readout-noise limits

Technical Needs

•Large telescopes, w ith A O system from the ground (> Lisa Poyneer) ‏

•Handling instrumental artefacts: design, active correction, calibration

Im pressive Evolution

G Q l u p

ESO3.6m/Come-On+ 1994 VLT/NACO 2005 Observing Challenge and Technical Needs Technical and Challenge Observing

(Janson et al. 2007)‏ (Neuhäuser et al 05)

7 Technical Needs

•Large telescopes, w ith A O system from the ground

•Handling instrumental artefacts: design, active correction, calibration

•Coronography

- Occulting Mask Saturated Imaging

- Lyot Coronography Observing Challenge and Technical Needs Technical and Challenge Observing

Technical Needs

•Large telescopes, w ith A O system from the ground

•Handling instrumental artefacts: design, active correction, calibration

•Coronography

D etection Lim its:

H - b a n d Observing Challenge and Technical Needs Technical and Challenge Observing

Obs. Tim e ~10m in

Star, H = 5 -6

(d = 50 pc) ‏‏

8 Technical Needs

•Large telescopes, w ith A O system from the ground

•Handling instrumental artefacts: design, active correction, calibration

•Coronography

•Differential techniques: ADI, SDI, Polarimetry

H ST roll angle (Low rance et al. 99; 00; 05) ‏‏

Being revisited/optim ized, for obs.

procedures and data analysis

(M arois et al. 2 0 0 6 ) ‏‏

D etails dependent on telescope,

Focus, defects origin and structure …

Observing Challenge and Technical Needs Technical and Challenge Observing > C . M arois's Talk

> J. Farihi and D . Lafrenière T alks

Technical Needs

•Large telescopes, w ith A O system from the ground

•Handling instrumental artefacts: design, active correction, calibration

•Coronography

•Differential techniques: ADI, SDI, Polarimetry

M ethane-rich com panion, T2-T8 BDs

SDI Concept:

CFHT/TRIDENT

(Racine et al. 1 9 9 9 ; M arois et al. 2 0 0 0 ) ‏‏

R e s u l t s : (M cCaughrean et al. 1994;

C lose et al. 2 0 0 5 ; Biller et al. 2 0 0 6 ) ‏‏

> B . B iller's T alk Observing Challenge and Technical Needs Technical and Challenge Observing

> G . M ontagnier's Talk

9 Outline

I- Brief introduction First discoveries (Gl299B, 51 Peg b). Development of new observing techniques. Advantage of direct imaging to explore the 5-500 AU missing link.

II- Observing challenge & technical needs Faint companion close to bright stars. Observing Limitations. Technical needs: AO, Coronography, Differential Imaging...

VI- Conclusion & perspectives

Spirit of Lyot Conference, Berkeley, June 2007

Target Selection: Stars near the Sun

Distance < 100 – 2 0 0 p c ‏ Target Selection & Main HAR and HC imaging Surveys imaging HC and HAR Main & Selection Target

10 Target Selection: Age

Stars M > 75 M Jup

B D s 13 < M < 75 M Jup

EGPs M < 13 M Jup Target Selection & Main HAR and HC imaging Surveys imaging HC and HAR Main & Selection Target

(Burrows et al. 2001)‏

1) Young, nearby Associations

Age (< 100 M yr)

Distance (< 100 pc) ‏

- 1983. TW Hya, an isolated T Tauri star (Rucinski & Krautter 1983)‏

- 1997. Identification of 5 first members of the TWA Association (Kastner et al. 1997)‏

- Now. 5 associations: TWA, β Pictoris, AB Dor,Tucana/Horologium & η Chameleontis + New stars from the SACY survey

> Total of 200 - 300 young, nearby (AFGKM) stars‏

Identification Groups: 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

Target Selection & Main HAR and HC imaging Surveys imaging HC and HAR Main & Selection Target - Li Abundance X-ray Activity - Stellar Kinematics RV and proper motions

11 1) Young, nearby Associations

Age (< 100 M yr)

Distance (< 100 pc) ‏

T ypical detection lim its: M > 1 M at physical separations > 10 - 40 A U B j u p

To search for and to characterize planetary m ass com panions

- HST/NICMOS Corono 45 Lowrance et al. (1999, 2000, 2005)‏ - Keck/NIRC AO-Corono - MacIntosh et al. (01); Kaisler et al. (01) - ESO3.6m/ADONIS AO-Corono 29 Chauvin et al. (2002, 2003)‏ - NTT3.5m/Sharp Saturated 32 Neuhäuser et al. (2003, 2005)‏ - VLT/NACO AO-Saturated 28 Masciadri et al. (2005) - VLT/NACO AO-Lp 22 Kasper et al. (2007)‏ - VLT & MMT AO-SDI 45 Biller et al. (2007), Close et al. (2005)‏ > Beth Biller's Talk Target Selection & Main HAR and HC imaging Surveys imaging HC and HAR Main & Selection Target

T W A 5 B H R 7 3 2 9 B G S C 8 0 5 7 B A B P i c B

(Low rance et al 1999) (Low rance et al 2000) (Chauvin et al 2003) (Chauvin et al 2005)

1) Young, nearby Associations

Age (< 100 M yr)

Distance (< 100 pc) ‏

T ypical detection lim its: M > 1 M at physical separations > 10 - 40 A U B j u p

To search for and to characterize planetary m ass com panions

- HST/NICMOS Corono 45 Lowrance et al. (1999, 2000, 2005)‏ - Keck/NIRC AO-Corono - MacIntosh et al. (01); Kaisler et al. (01) - ESO3.6m/ADONIS AO-Corono 29 Chauvin et al. (2002, 2003)‏ - NTT3.5m/Sharp Saturated 32 Neuhäuser et al. (2003, 2005)‏ - VLT/NACO AO-Saturated 28 Masciadri et al. (2005) - VLT/NACO AO-Lp 22 Kasper et al. (2007)‏ - VLT & MMT AO-SDI 45 Biller et al. (2007), Close et al. (2005)‏ > Beth Biller's Talk and more results to come - HST/NICMOS Corono 109 > Jay Farihi's Talk - Gemini/GPDS AO-ADI 85 > David Lafreniere's Talk

Target Selection & Main HAR and HC imaging Surveys imaging HC and HAR Main & Selection Target - VLT/NACO AO-Corono - Melo et al.; Chauvin et al. - Gemini/NICI AO-Corono - Liu et al.

12 2) Intermediate-old Stars

A ge (0.1 - 1.0 Gyr)

D istance (< 20 - 50 pc) ‏

T ypical detection lim its: M > 1 0 M (> 10 - 20 A U) ‏ B j u p

BD com panion study: Extension of the BD desert at interm ediate separations?

- Gemini/Hokupa'a Classical 31 Potter et al. (2002)‏ - Keck/NIRC AO-Corono 102 McCarthy & Zuckerman (2004)‏ Lick/GEMINI AO-Corono 178 - Palomar PALAO AO-Corono 101 Metchev et al. (2005, 2006)‏ KeckII/NIRC2 - Spitzer Classical-midIR 73 Luhman et al. (2006)‏

HD130948 BC H D 4 9 7 9 7 B H D 2 0 3 0 3 0 B H N P e g B

(Potter et al 2002) (M etchev et al 2004) (M etchev et al 2006) (Luhm an et al 2006) Target Selection & Main HAR and HC imaging Surveys imaging HC and HAR Main & Selection Target

3) Very Nearby Stars

A ge (0.1 - 10.0 Gyr)

D istance (< 10 - 30 pc) ‏

T ypical detection lim its: M > 2 0 M (1Gyr) and M > 6 0 M (10 Gyr) at (> 1 - 10 A U) ‏ B j u p B j u p

BD com panion study: Extension of the BD desert at interm ediate separations?

> V olum e-lim ited sam ple of A FGKM stars

- 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, 2006)‏

- Palomar PALAO AO-Corono EPIcS sample > A. Tanner's Talk Target Selection & Main HAR and HC imaging Surveys imaging HC and HAR Main & Selection Target

H R 7 6 7 2 B G l 2 2 9 B

(Liu et al 2 0 0 2 ) (N akajim a et al 1995)

13 3) Very Nearby Stars

A ge (0.1 - 10.0 Gyr)

D istance (< 10 - 30 pc) ‏

T ypical detection lim its: M > 2 0 M (1Gyr) and M > 6 0 M (10 Gyr) at (> 1 - 10 A U) ‏ B j u p B j u p

BD com panion study: Extension of the BD desert at interm ediate separations?

> V olum e-lim ited sam ple of A FGKM stars

> Focused on M stars

- 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)‏ ‏ Target Selection & Main HAR and HC imaging Surveys imaging HC and HAR Main & Selection Target

S C R 1 8 4 5 B

(B iller et al 2 0 0 6 )

3) Very Nearby Stars

A ge (0.1 - 10.0 Gyr)

D istance (< 10 - 30 pc) ‏

T ypical detection lim its: M > 2 0 M (1Gyr) and M > 6 0 M (10 Gyr) at (> 5 - 10 A U) ‏ B j u p B j u p

BD com panion study: Extension of the BD desert at interm ediate separations?

> V olum e-lim ited sam ple of A FGKM stars

> Focused on M stars

> L and T dwarfs multiplicity studies Bouy et al. (2003); Gizis et al. (2003)‏ Reid et al. (03): Burgasser et al. (2003)‏ Target Selection & Main HAR and HC imaging Surveys imaging HC and HAR Main & Selection Target

14 4) Stars with RV planets & RV drifts

A ge (0.1 - 10.0 Gyr)

D istance (< 50 pc) ‏

T ypical detection lim its: M > 2 0 M (1Gyr) and M > 6 0 M (1 0 G yr) at (> 1 0 - 2 0 B j u p B j u p AU) ‏

> Stars with RV planets

M assive com panions at long-periods?

D ynam ical im pact on inner planetary system s?

- KeckII/kCam AO-Saturated 25 Luhman & Jayawardhana (2002)‏ - NTT/Sofi Classical-Saturated - Mugrauer et al. (2004, 2006, 2007)‏ - VLT/NACO AO-Corono 26 Chauvin et al. (2006, 2007) - VLT/NACO AO-Classical 103 Eggenberger et al. (2007)‏ - Spitzer Classical-midIR 48 Luhman et al. (2006)‏

> Stars with long RV trends

Target Selection & Main HAR and HC imaging Surveys imaging HC and HAR Main & Selection Target - VLT/NACO AO-SDI > G . M ontagnier's Talk

and more.....

• Star Forming Regions (1-120 Myr and >100 pc)

Chameleon, Pleiades, Taurus substellar IMF Studies VLM multiplicity

> A. Tanner's Talk D H T a u B G Q L u p B C H X R 7 3 B (Itoh et al 2 0 0 5 ) (N euhäuser et al 2005) (Luhm an et al 2006)

• Young Brown dwarfs

Favorable Contrast IR-AO, LGS-AO

> L. Close's Talk 2 M 1 2 0 7 B (Chauvin et al 2004)

• White dwarfs

GD 165 B (Becklin & Zuckerman 1988)‏ Fossil of planetary system? Target Selection & Main HAR and HC imaging Surveys imaging HC and HAR Main & Selection Target

15 Outline

I- Brief introduction First discoveries (Gl299B, 51 Peg b). Development of new observing techniques. Advantage of direct imaging to explore the 5-500 AU missing link.

II- Observing challenge & technical needs Faint companion close to bright stars. Observing Limitations. Technical needs: AO, Coronography, Differential Imaging...

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 Observing Strategy & Main Results Main & Strategy Observing

16 2/3- Astrometric Follow-up Observations

Background object or physical companion ?

Proper motion study of AB Pic b

AB Pic A: Observing Strategy & Main Results Main & Strategy Observing - Proper motion - Parallactic Motion

Follow-up at several epochs

3/3- Photometric & Spectroscopic Characterization

•Photometry versus predictions evolutionary modelsa •Identification of atomic and molecular lines: H20, CO, CH4, FeH, NaI, CaI, KI… •Confirmation of a cool atmosphere

H2O H2O AB Pic B

M ~ 10-20 Mjup et Sep = 260 AU Spectral Type ~L1

!! Gliese 86 B case !! same nIR L/colors for BD or WD

12 4-2 NaI CO 2-0 3-1 5-3 Observing Strategy & Main Results Main & Strategy Observing AB Pic B 2M0345 (L1)‏

17 Results: Substellar companions of nearby stars

1 9 9 5 1 9 9 8 2 0 0 0 2 0 0 2 2 0 0 4 2 0 0 6

TWA5 B HR7329 B GSC8048 B DHTau B GQ Lup B CHXR73 B

HD130948 BC HD49197 B Gl577 BC AB Pic B SCR1845 B

Gl229 B G 1 9 6 - 3 B HR7672 B 2M1207 B HD203030 B

HNPeg B Observing Strategy & Main Results Main & Strategy Observing - GGTau B - G l 5 7 0 D - G J 5 8 4 C - ε I n d i B a b HD3651 B

- GJ1001 BC - G J 3 3 7 CD

AO, HST - Gl569 Bab - Gl1048 B - G l 4 1 7 BC

Large Surveys, Classical Imaging

Spitzer

Results: Physical and Chemical Properties

Thermal Emission:

L (Teff & R) Mass, Age, composition (& Formation)‏

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

Observing Strategy & Main Results Main & Strategy Observing Stellar kinematics, Dust lumikosity Li abundance, Stellar rotation Stellar activity: X-ray, Hα, emission lines

18 Results: Physical and Chemical Properties

d , a g e

nIR photometry L, Teff, 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)‏ Observing Strategy & Main Results Main & Strategy Observing Lyon: Allard et al. (2001; 2003)‏ ‏ ‏

Results: Physical and Chemical Properties

d a g e nIR photometry L Teff, R, M

Spectral Type (Old field BDs) Evol. Interior Models nIR spectroscopy Spectral indexes (H2O, CO, CH4)‏ Bolometric corrections

Young / Old M, L dwarfs: 2MASS 0141; L0-L2 (Kirkpatrick et al. 06)‏

AB Pic B (10-20 Mjup; 260 AU)‏ Spectral Type ~L1 (Song et al. 2006)‏ Observing Strategy & Main Results Main & Strategy Observing

19 Results: Physical and Chemical Properties

d a g e nIR photometry L Teff, R, M

Spectral Type (Old field BDs) Evol. Interior Models nIR spectroscopy Spectral indexes (H2O, CO, CH4)‏ Bolometric corrections

d log(g), Teff R, M, L, age Synthetic spectra of substellar atmospheres > Molecular, dust opacities. Dust Formation/condensation > Boundary conditions on interior calculations Observing Strategy & Main Results Main & Strategy Observing Tucson: Burrow et al. (2001; 2002; 2006)‏ NASA-Ames: Marley et al. (1999; 2002)‏ Lyon: Allard et al. (2001; 2003)‏ ‏

> K. Luhm an's Talk

Results: Physical and Chemical Properties

M . M arley's Talk: > Uncertainties w ith Evolution and A tm ospheric M odels

initial C onditions Cloud M odelling

Convection Rem aining lines

Form ation m echanism s Com position

 M o d e l s : need to be calibrated for young (<100 M yr) ages and very low m asses

> D ynam ical m asses: Eclipsing Binary, D isk Kinem atics, A strom etry & Spectroscopy

DM Tau, CY Tau (Sim on et al. 2000) ‏

HD98800 AB (Boden et al. 2005) ‏

T W A 5 A a b (Konopacki et al. 2007) Observing Strategy & Main Results Main & Strategy Observing 2MASS0535 AB (Stassun et al. 2006)

A B D o r (Close et al. 05, 07; Luhm an et al. 2006) ‏

> A . Boccaletti's Talk ‏

20 Results: Physical and Chemical Properties

M . M arley's Talk: > Uncertainties w ith Evolution and A tm ospheric M odels

initial C onditions Cloud M odelling

Convection Rem aining lines

Form ation m echanism s Com position

 M o d e l s : need to be calibrated for young (<100 M yr) ages and very low m asses

> D ynam ical m asses: Eclipsing Binary, D isk Kinem atics, A strom etry & Spectroscopy

> H R-resolution spectroscopy in optical + A tm ospheric M odels

(M ohanty et al. 2004a, 2004b) ‏ Observing Strategy & Main Results Main & Strategy Observing

Results: Substellar companions of nearby stars

Large Surveys

Radial Velocity

HC & HAR Im aging

Transits

µ Lensing Observing Strategy & Main Results Main & Strategy Observing

21 Results: 2M1207B, First Planetary Mass Companion?

MA ~ 24 MJup

MB ~ 8 MJup

Formation scenario?  Core-accretion (Pollack et al. 1996)‏

 Disk Instability (Boss 1997)‏

 Collapse/Fragmentation (stars & BDs)‏ - M > 0.3 M 2M1207B, (Chauvin et al. 2005; Lodato et al. 2005)‏ disk A - Tcore Accr. > 10 Myr •> Opacity limit for fragmentation reached (Larson 1969)‏

Observing Strategy & Main Results Main & Strategy Observing •> Overlap between formation mechanisms

•Other substellar companions (HC & HAR imaging):

•> Mass ratio, wide separation star/BD formation mechanism

•Soon, some ambiguous cases?

Results: Detection Limit Interpretation

Young, Nearby Star

G K s t a r

K ~ 7

Age ~10 Myr

d ~ 3 0 p c Observing Strategy & Main Results Main & Strategy Observing

Evol. M odel

(Baraffe et al. 0 3 ) ‏

22 Results: Statistical Analysis

Detection Limits (minimum mass, projected physical separation)

Monte Carlo Simulations

Physical properties (mass, a, e)‏ of EGP and BD companion population Observing Strategy & Main Results Main & Strategy Observing Formation mechanisms of BDs & EGPs

Results: Statistical Analysis

Young (10-30 Myr), nearby stars: Population of EGPs at wide orbits?

α - Probability Distributions: Semi-major axis P(a) ~ a [0.3 – amax] AU

Eccentricity e = 0; RV distribution a -1.5 EGP Mass P(m) ~ m [1 - 50] Mjup I n p u t s

- adjustement with RV surveys (3%, 1-3 AU, > 1 Mjup, Marcy et al. 2005)‏

MC Drawing: Comparison with detection limits & null-detection

Probability for an EGP population to be consistent with the survey

Results: VLT/NACO-Lp (Kasper et al. 2007)‏

Small outer radii (amax < 15 AU) and Decreasing radial distrib. (α<0)

Observing Strategy & Main Results Main & Strategy Observing MMT-VLT/SDI (Biller et al. 2007) > Poster by E. Nielsen

Rule out combination of M, e, constant-a distributions, amax

> Observational constraints on the outer part of the planetray systems

23 Results: Statistical Analysis

Very nearby MS stars: BD desert at intermediate separations?

- Set of simulated orbits: a, e, i, ω (Carson et al. 2006; 2007)‏ - BD Mass function similar to SFRs I n p u t s

MC Drawing: Comparison with detection limits & null-detection

Fraction of BD companion

Results: BD desert studies revisited for intermediate separations

fBD of 0.0 – 9.3% for a =[25 – 100] AU

RV: fBD < 1% for a < 3 AU (Marcy & Butler 2000)‏ Observing Strategy & Main Results Main & Strategy Observing > 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 5-500 AU missing link.

II- Observing challenge & technical needs Faint companion close to bright stars. Observing Limitations. Technical needs: AO, Coronography, Differential Imaging...

VI- Conclusion & perspectives

Spirit of Lyot Conference, Berkeley, June 2007

24 Conclusions

- HC and HAR Direct Imaging: - complementary to other techniques (RV, transit...)‏

- Spectral characterization, orbit monitoring

- Missing link between 5 – 500 AU

- Impressive evolution: - Technique: telescope, AO, observing modes

- Target selection (Young, nearby associations)‏

- Key results: - increasing number of substellar companions since 1995

- Importance of atmosphere and evolution models

- access to planetary mass companions Conclusions & Perspectives & Conclusions > 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:

NTT/Sofi, HST/NICMOS, GDPS-ADI Gemini/NICI, VLT/NACO SACY survey AEOS/Lyot project

- Horizon 2010

Subaru/HiCIAO Gemini Planet Imager

Conclusions & Perspectives & Conclusions VLT/SPHERE

> Session (tomorrow): Futur Instruments & Telescopes