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Direct Imaging of Extrasolar Planets Overview of Ground & Space Programs Anthony Boccaletti : Obs. Paris-Meudon. Outline. 1. A brief introduction to the high contrast imaging problematic 2. A brief review of projects (talks to follow) 4. « Where » do we need to direct our effort.
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Direct Imaging of Extrasolar PlanetsOverview of Ground & Space ProgramsAnthony Boccaletti : Obs. Paris-Meudon
Outline 1. A brief introduction to the high contrast imaging problematic 2. A brief review of projects (talks to follow) 4. « Where » do we need to direct our effort
No longer a dream ! Detection was made possible because : - small mass ratios (contrast is lower) - young ages (planet is brighter) - large physical / angular separations
Problematic STOP !!!! … What about diffraction ??? Planets are faint and close …. 109 = 1 milliard 106 = 1 million Reflected light Thermal emission
Problematic Stellar images are not point-like …
Solutions to reduce diffraction We need BIG telescopes … We need to attenuate the star Yes but … the Sun is an extended source Stars are point sources => diffraction is much stronger We need more performant stellar coronagraphs … to attenuate stars
Plan A: si Plan B: Plan C: Plan D: In Theory …
Problematic (again) Instruments are not perfect …. unfortunately • Many defects : • - atmospheric turbulence for ground based telescopes • static (more or less) optical aberrations • variation of transmission • alignment • chromaticity • … => Limits the performance of coronagraphs
JPL Testbed SCC simulation SDI, Gemini ADI, Gemini SD, VLT Solutions to reject speckles Wavefront Correction : at focal plane - speckles minimization - Self Coherent Camera • Wavefront Calibration : • Differential imaging • spectral (SDI, SD) • angular (ADI) • polarimetric (PDI)
Planet Finders on 8m telescopes (2011) eXtreme AO + coronagraphy + differential imaging HiCIAO European Consoritum, VLT - Dual band NIR camera (YJHK) - NIR IFS (YJH) - Dual Polarisation VIS camera • Japan, Subaru • Dual band NIR camera • Dual polarisation NIR camera • HiCIAO + (in dev., 2010) • Focal Plane WF • coronagraph improvement • - NIR IFS • US, Gemini South • NIR IFS (YJH) • Focal Plane Looking at Giant Planets in : - young associations of stars (10 Myrs <100pc) - stars with known planets (RV surveys) - stars of intermediate age (0.1-1 Gyr) - very nearby bright stars
US instrument 0.6 - 5 m imager NIRCAM has 5 coronagraphs Optimized for several filters (F200, F480, …) Good performance at 4.8m At 2.2 m mature giants are too faint. Expected contrast : 105 - 106 - photometry (R=10-20) l=11.40mm James Webb Space Telescope (2014) MIRI & SPICA NIRCAM MIRI Europe + US consortium 5 - 28 m imager + IFU MIRI imager has 4 coronagraphs 4QPM in 3 filters (10.6, 11.4, 15.5 m) => self luminous mature giants T > 300-400K (5 - 10AU, 10pc, 5Gyr) Expected contrast : 104 - 105 - photometry (R=20) FGS - TFI CSA responsabilty 1 - 5 m tunable filter with coronagraphic capabilities (Spectral Deconvolution) - spectra (R=100)
Extremely Large Telescopes (2020) heritage of SPHERE / GPI / HiCIAO /D = 10mas- Photometry + spectra heritage of VIZIR & MIRI /D = 50mas Photometry + spectra objectives : - young giants - mature giants, spectral characterization - Super Earth : detection + 1st order charac. • objectives : • mature giants • irradiated planets
Future projects … in space • Extend spectroscopic characterization towards ; • shorter wavelengths (<1 m) • lower masses (Super Earths, Earths) • shorter separations (< 1 AU) • older objects (1 - 5 Gyr) • more distant stars (> 100 pc) • …
Single spacecraft (later than 2020) • Small Telescopes : 1.5 - 2m • - optical quality • - efficient coronagraph • focal plane WFS and correction • differential imaging • 3 studies in the US : • PECO • ACCESS => Probe Class (Decadal Survey) • EPIC • SEE-COAST => CV proposal • - spectra : 0.4 - 1.0 m (R>50) • - polarimetry : 0.4 - 0.85 m • objectives : • - explore diversity of planets • - mature giants in the visible • Super Earths • target list : HARPS, ESPRESSO, GAIA, COROT, KEPLER, …
Two spacecrafts: towards tellurics External Occulter Fresnel imaging lens Occulter : 50 m Telescope : 4 m Separation : 80 000 km Optimize for Vis. and UV : 0.4 -1.1 m Chromatic High throughput Lens : 3.6 m Telescope : 68 cm Separation : 2.5 - 20 km Optimize for Vis. and UV : 0.1 -1 m Chromatic Low throughput
HST Vis JWST NIR + MIR old / close EGPs 2014 1995 2000 2007 2011 2017-2020 4m + AO Silla, CFH NIR 30 - 40 m + XAO EPICS / PFI NIR + MIR old EGPs / Super Earth 8m + XAO SPHERE / GPI / HiCIAO NIR young / massive / close EGPs 8m + AO VLT, Keck, Gemini NIR Timeline SPACE Room for missions ! Vis / MIR - old EGPs - Super Earths - Earths GROUND
Mass vs. Wavelength coverage Space telescopes 10 MJ 1 MJ Space Interferometry 10 M Occulters 1 M
A few conclusions … high contrast imaging allows to study molecules in the atmosphere of a wide variety of objects see the talks of this afternoon for details most instruments focused on EGPs in the NIR & MIR There is a gap between EGPs and Earth-like planets spectrocopy What’s next (short timescale) : - spectroscopy of EGPs in the visible - Super Earths are numerous - MIR : space interferometry more promising (see talk this afternoon)