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DARWIN in SPACE The Quest for LIFE beyond the Solar System

DARWIN in SPACE The Quest for LIFE beyond the Solar System. Stockholm Observatory (6th floor). Contributors. Very Many People. Robin Laurance [1999] Jean-Marie Mariotti [1998]. Announcement. Towards Other Earths 22 – 25 April 2003 Heidelberg, Germany

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DARWIN in SPACE The Quest for LIFE beyond the Solar System

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  1. DARWIN in SPACE The Quest for LIFE beyond the Solar System Stockholm Observatory (6th floor)

  2. Contributors Very Many People... Robin Laurance [1999] Jean-Marie Mariotti [1998] Announcement Towards Other Earths 22 – 25 April 2003 Heidelberg, Germany web page: www.mpia.de/DARWIN e-mail: darwin@mpia.de

  3. Outline Interdisciplinary Talk Astrophysics Biology Chemistry Philosophy... Introduction - Formation of Stars and Planets Scientific Goals Statement of the Problem Adopted Solution Current Developments and Implementation Look into the Future

  4. DARWIN … is a vessel Detecting and Analysing Remote Worlds with Interferometric Nulling

  5. Theory of Star & Planet Formation * * 1 AU = 150 Million km 1 pc = 200 000 AU 1 pc = 3 lightyears

  6. Observational Evidence - Newly Formed Star supersonic plasma jet protoplanetary disk + hidden star Hubble Space Telescope

  7. Observational Evidence for exo-Planets Observing the STARS P = 1 yr Earth: 100 000 km/h Sun: 0.3 km/h 1 AU M sin i

  8. Observational Evidence for exo-Planets:observing the Stars 1995: THE Breakthrough – 51 Peg 100 50 0 -50 -100 V (m/s) Mayor & Queloz 1995 Nature 378, 355 0 0.5 1 Phase

  9. Observational Evidence for exo-Planets: observing the Stars

  10. Observational Evidence for exo-Planets: Observing the Stars Planetary Hypothesis = true Planetary Mass = 0.7 MJupiter Planetary Radius = 1.4 RJupiter I (%) 100 99 98 HD 209458 - HST -0.1 0.0 0.1 t – t0 (days)

  11. 2002 >100 exos M = O(MJupiter) ``Hot Jupiters´´ http://exoplanets.org/

  12. Mass Distribution Function of Exos => Existence of Many Earth-like ?

  13. ...does not provide this Radial Velocity Technique

  14. Stating the GOALS [ 1 ] find Earth like Planets [ 2 ] look for signs of Life ?...piece of cake...?

  15. [ 1 ] Finding exo-Earths Short Lifetime Brown Dwarfs Different Stellar Temperatures – needs Variable Resolution

  16. [ 2 ] Identifying LIFE What does ALL Life DO? Origin of Life? Definition of Life? Life Produces WASTE !

  17. Statement of the Problem Earth like planet ? with LIFE? 51 Pegasi

  18. Possible Solutions – Possible Techniques • Radial Velocity: NOT feasible (9 cm/s; contamination • by convection and big planets) • Astrometry: feasible from SPACE (<3 marcsec) • Occultation: feasible from SPACE (<0.01%) • Micro Lensing: single event (hours; little information) • …needs observatories in SPACE!

  19. Selection of Spectral Region Scattered Stellar Radiation Planetary Thermal Emission log10 => Space! Visible InfraRed

  20. Selection of Observational Method Two (known) possibilities: • Coronograph in Space •  Telescope > 30 m •  NOT Realistic! • New Concept • “Nulling’’ Interferometer in Space •  Telescopes = 1.5 - 3.5 m •  Base Lines = 30 - 500 m •  Feasible! this is it!

  21. Interferometry We gain resolution... So, what do we loose? Image information content

  22. D Filled aperture D: contains all spatial frequencies up to 1/D => Image of the source B d/2 Interferometer B: picks out 1 spatial frequency 1/B in coherent field of view 1/d Example:l = 10 mm, B = 200 m, d = 2 m Resolution = 10 milliarcsec Field of view = 1 arcsec

  23. Nulling Interferometer: Point Sources simplest case: 2 element Bracewell interferometer to``null´´ stellar radiation e.g. at 10 pc distance Sun m10 mm= 3.6 (1.6 Jy)* Earth m10 mm= 20.7(0.23 mJy) = star on optical axis q = 0 ``flat bottom´´ High Rejection Rate: > 105 *1 Jy = 10-26 W m-2 Hz-1

  24. nulled Sun Venus Earth DARWIN Simulation of Solar System at 10 pc distance Date: January 1, 2001 Ecliptic inclined by 30° Mars Mennesson & Mariotti (1997) WHAT is observed (1) Multi-Epoch Imaging Discovery of Earth like exo-Planets

  25. WHAT is observed (2)Spectroscopy CO2 CH4 H2O O3 …. • Physics & Chemistry of Planetary Atmospheres IR Spektra – Fingerprints of the Planets • IR emission: 300K BB • continuum radiation • IR absorption: • spectral lines

  26. 6 8 10 12 14 16 18 The Living Atmosphere THE BIOmarkers! Venus, Earth & Mars Intensity CO2 O3 H2O H2O Sagan et al. 1993 Nature 365, 715 Wavelength (mm)

  27. Oxygen Photosynthesis 2H2O + CO2 + 8hn CH2O + O2 + H2O O2 O2 + O + M  O3 + M O3 6 8 10 12 14 16 18 wavelength (m) The Search for Biospheres Life on Earth as a reference: C-based chemistry in H2O solution ….produces Oxygen

  28. Oxygen Production = Life? same processes that produce abiotic O2destroy O3 (radicals from H2O photolysis)or mask the O3 signature (CO2 absorption) Claim: photochemistry CANNOT reproduce triple signature of oxygen photosynthesis O3 - CO2 - H2O Selsis et al. 2002, Astron. & Astrophys. 388, 985

  29. DARWIN 2 Three-DACs (Laurance) = 6 Telescopes (Free Flyers) 1 Hub (Beam Combiner) + 1 Master Satellite IRSI InfraRed Space Interferometer www.esa.int/home/darwin/

  30. Orbit of DARWIN @ Sun-Earth L2 toward the Sun toward the Sun top view 500.000 km side view

  31. Noise Control - Backgrounds Stellar Leaks Zodiacal Background Exo-Zodi Photon Noise from Planet

  32. Noise Sources

  33. Target Selection • Signal-to-Noise(S/N) (t int)Stellar Leak~LStarD2 RPlanet- 4  optimised systems: - LowLStar : Cool Stars (M, K) - Nearby: < 100 pc - Big Planets:> 0.1 RTellus - Not in (close)Stellar Binaries • Angular Resolution(for planet in Habitable Zone) • Planet = 100 (LStar / LSun)1/2 (1/D10pc) [mas] • adjustableconfiguration (unresolved stellar disk)

  34. someMajor Performance Requirements Nulling of on-axis-Star > 105 Baseline Accuracy 1 cm (rms) Optical Path Difference 20 nm (rms) Telescope Pointing 24 mas (rms) Amplitude Matching < 10-2

  35. Ongoing Developments & Future Planning Joint Mission 22 april 2002 GENIE (VLTI) 2003 COROT (occultation) 2004 SMART-2 (ff, metrol) 2006 Eddington (occult.) 2008 Kepler (NASA) 2009 JWST (``NGST´´) 2010

  36. Ongoing Developments & Future Planning Conclusions: [1] find exo-Earths [2] find signs of Life Darwin can do it! Launch on Ariane-5 5E/CB 2013 - 2015

  37. Towards Other Earths Darwin/TPF and the Search for Extrasolar Terrestial Planets 22 – 25 April 2003 Heidelberg, Germany web page: www.mpia.de/DARWIN e-mail: darwin@mpia.de

  38. The End

  39. Hydrodynamics of Star Formation

  40. Earth and Cows

  41. UV UV UV escape H2O CO2 CO2 OH CO CO H O O O O2 O2 O2 abiotic = photochemical O2 production

  42. Abotic Production of O2 by H2O Photolysis Selsis et al. 2002, Astron. & Astrophys. 388, 985 CO2 Intensity H2O H2O O3 Wavelength (mm)

  43. Cyanobacteria the oxygen producers oxygenic photosynthesis: 2H2O + CO2 + hn CH2O + O2 + H2O

  44. The late Rise of Oxygen(2.2-1.9 Gyrs ago) PO2 < 1 % P.A.L PO2 > 15 % P.A.L 3.0 2.8 2.6 2.4 2.2 2.0 1.8 1.6 1.4 1.2 1.0 0.6 0.8 Time (Gyrs) Holland, 1993

  45. 50 mbar of CO2 1 bar of CO2 0,3 mbar of CO2 water escape Solar luminosity CO2 greenhouse effect not anymore efficient Temporal evolution of the Habitable Zone Kasting et al. 1993 4 2 time (Gyr) 0 -2 -4 0,5 1,0 1,5 2,0 2,5 3,0 3,5 AU

  46. CH4 required for surface liquid water present CO2 CO2 > present CO2 O2 < 1 % present O2 O2 > 15 % present O2 Temporal evolution of the Sun

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