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Exo-planets: ground-based How common are giant planets? What is the distribution of their orbits? –3.6m HARPS: long-term radial velocity monitoring of large samples to 1 m/s => Saturns out to ~5 AU –VLT-AO/OWL: Direct imaging of giant planets; complement to JWST NIRCAM/MIRI direct detection –VLTI (10 as)/ALMA (100 as): astrometry => >10 M Earth out to large AU; complement to GAIA, which can observe much larger sample but for shorter period Ewine van Dishoeck, ESO-ESA coordination meeting, September 15 2003, Garcching
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Planetary search methods Perryman 2000
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Planetary search methods Perryman 2000 - HARPS 1 m/s => > Saturn out to 5 AU with 10 yr monitoring - VLTI 10 mas => > 10 M Earth in terrestrial planet forming zone
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Giant planets (cont’d) How do giant planets affect terrestrial planet formation? Inward migration, ejection of remnant planetesimals, pumping up of i,e –Link ground-based giant planet systems with space-based searches for Earth-like planets? Free-floating/isolated exo-planets and brown dwarfs => formation from disk or fragmenting cloud? –VLT/JWST searches in/near star-forming regions (younger objects have larger luminosities)
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Giant planets (cont’d) Planetary atmospheres: composition => thermal properties, mass, age –VLT, OWL => high-res spectra; complements JWST NIR, MIRI spectrophotometry and low-res spectra
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Ground-based spectrum of nearest T dwarf Scholz et al. 2003 Need space to observe critical H 2 O and CH 4 bands
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Model exo-planetary atmospheres Note change in mid-infrared spectral features with age Based on Burrows et al. 1997
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Exo-earths with OWL Sun is ~10 10 times brighter than Earth at VIS –concentrate light as much as possible –make separation as large as possible both D and Strehl must be very large OWL would see –Earth-like planets in HZ out to 30pc –cold Jupiters out to Pleiades (120pc) and beyond –hot Jupiters further out (but resolution) D=100m just enough for this (sensitivity D 4 ! ) Spectroscopy –Exo-biospheres? Gilmozzi 2003
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Solar system @10 pc Jupiter @5AU Earth @1AU OWL 100m J Band 80% Strehl 10 4 sec 0.4’’ seeing O.1’’ Gilmozzi 2003
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The answer lies in the past, during the time when the star and its planets are being assembled Simulation G. Bryden Why are exo-planetary systems different from our own? Theory Need spatially resolved images at mid-IR and mm
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Formation of planetary systems Massive gas-rich disks Tenuous debris disks Planet building phase M(gas + dust)=0.01 M sun t=few Myr gas + dust interstellar M(dust)<1 M earth t>10 Myr dust produced in situ - Time scale for gas and dust dissipation? => Jovian planet formation timescale - Time scale for dust settling and grain growth? - Planet formation mechanism: core accretion vs. disk instability - Physical structure disks (T, n, v, ….)? - Chemical evolution gas + dust
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Synergy ground-based facilities Dutrey et al. 2000
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Example: Vega debris disk SimulationPdB 1mm data Wilner et al. 2002 Dust trapped in resonances due to unseen planet with few M Jup ? star What ALMA and JWST are expected to see…
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Synergy between ground and space SIRTF/Herschel/submm bolometer arrays will detect (largely unresolved) mid- and far-infrared excesses around hundreds of stars of different age, luminosity, evolution stage, … ALMA and JWST-MIRI will have the sensitivity to detect and image dust in disks down to lunar masses at subarcsec resolution (down to 1 AU) out to distances of 300 pc VLTI-MIDI will be able to image the hot dust within few AU in brightest systems Herschel will provide peak luminosity and spectral energy distribution Complete spectroscopy 1 m to 3 mm of both gas and dust by combined VLT/JWST/Herschel/ALMA data in brighter systems GAIA essential to obtain accurate distances for analysis and statistics
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Disks around brown dwarfs Example of synergy between facilities 10 1hr -Brown dwarf with VLT -Peak disk luminosity with Herschel (unresolved except in nearest objects) -Mass + image cold dust and gas with ALMA -Image warm gas with VLTI ALMA VLT Herschel BD Disk Natta & Testi 2001
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Pathways to life? Based on Ehrenfreund & Charnley 2000 Search for building blocks of pre-biotic molecules
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Links between disks and comets - Pre-biotic gas-phase molecules in disks with ALMA - Ices in disks with VLT/JWST/OWL - Silicates, organic refractory material with VLT/JWST/OWL Silicates in disk: mid-IR CO ice in disk: IR Organics in protostars: mm Malfait et al. 1998 Thi et al 2002 Cazaux et al. 2003
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ALMA and JWST: perfect complement 0.3 - 7 mm 0.015 – few arcsec Thousands of lines by hundreds of gas- phase molecules CO as cold mass tracer Cold dust (10-100 K) 1 - 28 m 0.03 – 1 arcsec Major gas and solid- state species; PAHs; atomic lines Direct observation (warm) H 2 Warm dust (60-1000 K)
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