120 likes | 203 Views
P3 panel: exozodiacal disks. O. Absil & C. Eiroa with inputs from A. Roberge , D . Defrère , C . Beichman , W . Danchi , J .-C. Augereau, etc . Dust in planetary systems. We all live in a debris disk! Asteroid collisions Comet outgassing
E N D
P3 panel: exozodiacal disks O. Absil & C. Eiroa with inputs fromA. Roberge, D. Defrère, C. Beichman, W. Danchi, J.-C. Augereau, etc.
Dust in planetary systems • We all live in a debris disk! • Asteroid collisions • Comet outgassing • Dust is luminous (much more than the Earth) • Dust is expected in any planetary system Kuiper belt: 40 K, 50 AU Zodiacal disk: 300 K, 1 AU
Dust not uniformly distributed Observations Simulations Earth at 1 AU Stark & Kuchner 2008
The exozodi issue: visible imaging • 10-100 zoditolerable for closesttargets • Asymmetriesneedthorough investigation 2m 4m 6m 8m 12m
The exozodi issue: IR interferometry • Shot noise: 100 zodi tolerable in average • Preserves 75% of mission outcome • Asymmetries: ~10 zodi tolerable
But ... do we really care? • If Solar system is the rule, “Earth explorer” could just skip unsuitable systems • Can afford to loose some time • EZs interesting on their own • What if EZ mode is around 10 zodi? 100 zodi? • Is the distribution log-normal at all? Bimodal? 100 zodi? Bad systems 10 zodi? < 1 zodi? 0.01 0.1 1 10 100 1000
What we know: exo-Kuiper belts 100 × solar • Detected since 1984 • IRAS, ISO, Spitzer • Sensitivity ~ 100 × solar • Herschel • Down to 1 ×solar • Actual distribution will soon be known for the cold parts • What about warm parts? Bryden et al. 2006
What we want to know: exozodis • Mid-infrared most suited • Photometry • Spitzer: IRS, MIPS • Imaging • 10-m telescopes, (JWST) • Interferometry • Keck Nuller, VLTI/MIDI • Near-infrared can help • Interferometry • CHARA/FLUOR, VLTI/VINCI
Exozodis: where we stand • IRS, MIPS • 1000 zodi at 3-σ • Large sample • ~2% of systems • Keck Interferometer Nuller • 300 zodi at 3-σ • Small sample (on-going) • K-band interferometry • 1000 zodi at 3-σ • Small sample (on-going) • ~20% of MS stars with large amount of hotdust?? • EZs≠ from solar zodi?? KIN 300 zodi 0.01 0.1 1 10 100 1000
Whatneeds to bedone? • Solution #1 • Use models to connect Kuiper beltswithexozodis • Problem: planetary system architecture matters! • Solution #2 • Survey exozodisto buildhistogram • Whatshouldbe the goal sensitivity? • Probablyaround 30 zodi (3-σ) • Solution #3 • Characteriseexozodisaround all identifiedtargets • (need to wait for SIM or RV detections, and to reach 10 zodi)
Whatdoesittake? • LBTI • Expect ~30 zodiat 3-σ • Survey starting> 2012 • 60 targets: sufficient? • Other possible nullers • ALADDIN • Balloon • FKSI/Pegase • Other instruments • Small coronagraphs: needto beinvestigated
Conclusions / recommendations • Invest in modelling • Probability distribution (log-normal? bimodal? other?) • How deep is enough? 30 zodi? • Asymmetries: better predictions needed! • Invest in LBTI • Could greatly reduce the exozodi problem if it lives up to the expectations • Support development of other exozodi finders • ALADDIN, balloon, FKSI (share the same payload) • Small coronagraphs?