1. December 14, 2001MISU Page 1 DARWIN D etecting & A nalysing R emote W orlds through I nterferometric N ulling a vessel

2. December 14, 2001MISU Page 2 Darwin - the search for biospheres “Biosphere” = Planetary Atmosphere + Bioactivity

3. December 14, 2001MISU Page 3 Darwin - the search for biospheres Do planets outside the solar system exist?

4. December 14, 2001MISU Page 4 Darwin - the search for biospheres Hubble Space Telescope HH 30 protoplanetary disk HH 30 supersonic plasma-jet

5. December 14, 2001MISU Page 5 Darwin - the search for biospheres 1995 a breakthrough

6. December 14, 2001MISU Page 6 Darwin - the search for biospheres True mass & radius from...

7. December 14, 2001MISU Page 7 Darwin - the search for biospheres …planetary transit  observational proof! Exoplanets do exist! HD 209458 - Hubble Space Telescope

8. December 14, 2001MISU Page 8 Darwin - the search for biospheres

9. December 14, 2001MISU Page 9 Darwin - the search for biospheres Radial velocity survey: observation of >3000 G-M stars about 70 stars with exoplanets identified observational limit: about 1 m/s Similarities/differences wrt solar system (1) projected mass vs semimajor axis

10. December 14, 2001MISU Page 10 Darwin - the search for biospheres Similarities/differences compared to solar system (2) eccentricities

11. December 14, 2001MISU Page 11 Darwin - the search for biospheres Earth

12. December 14, 2001MISU Page 12 Darwin - the search for biospheres Search for exosolar Earth -type planets Radial velocities: <10 cm/s Astrometry: <3  arcsec (10 -11 rad) Dynamic range: VIS 10 9 MIR 10 7

13. December 14, 2001MISU Page 13 Darwin - the search for biospheres Search for exosolar Earth -type planets Radial velocities: <10 cm/s Astrometry: <3  arcsec (10 -11 rad) Dynamic range: VIS 10 9 MIR 10 7 log

14. December 14, 2001MISU Page 14 Darwin - the search for biospheres Needs large telescope for resolution and “mask” for contrast  telescope  30 m … in space!

15. December 14, 2001MISU Page 15 Darwin - the search for biospheres The masking device: a Nulling Interferometer with rejection  < 10 -5

16. December 14, 2001MISU Page 16 Darwin - the search for biospheres (2) to take IR-spectra of these x-tremely weak point sources i.e. an instrument that is capable (1) to image at high resolution x-tremely weak point sources

17. December 14, 2001MISU Page 17 Darwin - the search for biospheres (1) to image at high resolution x-tremely weak point sources DARWIN Simulation of Solar System at 10 pc distance Date: January 1, 2001 Ecliptic inclined by 30° nulled Sun VenusEarth Mars Mennesson & Mariotti (1997)

18. December 14, 2001MISU Page 18 Darwin - the search for biospheres (2) to take IR-spectra of these x-tremely weak point sources

19. December 14, 2001MISU Page 19 Darwin - the search for biospheres log

20. December 14, 2001MISU Page 20 Darwin - the search for biospheres 5 to 20  m region contains molecular bands …bio-markers... 681012141618 CO 2 H2OH2O H2OH2O O3O3

21. December 14, 2001MISU Page 21 Darwin - the search for biospheres Life on Earth as a reference: C-based chemistry in H 2 O solution ….produces Oxygen 681012141618 wavelength (  m) O2O2 O 2 + O + M  O 3 + M oxygen photosynthesis 2H 2 O + CO 2 + 8h  CH 2 O + O 2 + H 2 O O3O3

22. December 14, 2001MISU Page 22 Darwin - the search for biospheres But what about...

23. December 14, 2001MISU Page 23 CO CO 2 UV O2O2 O H2OH2O O H O2O2 OH escape CO CO 2 UV O2O2 O abiotic = photochemical O 2 production

24. December 14, 2001MISU Page 24 Darwin - the search for biospheres same processes that produce abiotic O 2 destroy O 3 (radicals from H 2 O photolysis) or screen the O 3 signature (CO 2 absorption) Claim: photochemistry cannot reproduce triple signature of oxygen photosynthesis O 3 - CO 2 - H 2 O

25. December 14, 2001MISU Page 25 Darwin - the search for biospheres But what about time evolution...

26. December 14, 2001MISU Page 26 -4 -2 0 2 4 0,51,52,53,51,02,03,0 AU time (Gyr) Kasting et al. 1993 1 bar of CO 2 50 mbar of CO 2 0,3 mbar of CO 2 CO 2 greenhouse effect not anymore efficient water escape Solar luminosity Evolution of the Habitable Zone

27. December 14, 2001MISU Page 27 CH 4 required for surface liquid water present CO 2 CO 2 > present CO 2 O 2 < 1 % present O 2 O 2 > 15 % present O 2 Evolution of the Sun

28. December 14, 2001MISU Page 28 H2OH2O CO NO NO 2 CO 2 SO 2 CH 4 H2OH2O ? ? 4.5 Gyr t ? Venus Earth Mars O3O3 CO 2 H2OH2O Evolution of the Planets

29. December 14, 2001MISU Page 29 Darwin - the search for biospheres...many questions to answer before during and after...

30. December 14, 2001MISU Page 30 DARWIN 6 Telescopes (Free Flyers) 1 Hub (Beam Combiner) 1 Master satellite IRSI InfraRed Space Interferometer

31. December 14, 2001MISU Page 31 ESA-Mission Launch: Ariane-5 Orbit (Sun-Earth):L2 Minimum Lifetime:5 yr Monolitic reflectors:6 (1.5 - 3 m) Darwin - the search for biospheres

32. December 14, 2001MISU Page 32 Orbit of DARWIN toward the Sun toward the Sun 500.000 km top view side view

33. December 14, 2001MISU Page 33 Technical Requirements DARWIN shall provide(better than) Nulling factor: 10 5 Base line accuracy : 1 cm Optical Path Difference :20 nm Telescope pointing : 24 mas Amplitude accuracy : 10 -2

34. December 14, 2001MISU Page 34 Time Line 2001 2005 Technical Development 2007 Definiton Phase Demo flight: SMART2 Building Phase 2013

35. December 14, 2001MISU Page 35 Darwin - the search for biospheres Conclusions DARWIN is an esa Cornerstone mission to detect & analyse Earth-like planets - space precursor(s): SMART2 ( and 3?) - esa/eso groundbased Nuller @ VLT Analysis needs atmosphere models

36. December 14, 2001MISU Page 36 Darwin - the search for biospheres

37. December 14, 2001MISU Page 37 Life on Mars?

38. December 14, 2001MISU Page 38 Life on Earth?

39. December 14, 2001MISU Page 39 Telescope: Free Flyers