1. Export Control Notice Export or re-export of information contained herein may be subject to restrictions and requirements of U.S. export laws and regulations and may require advance authorization from the U.S. Government. Detailed Spectroscopy of Exoplanets with The New Worlds Observer Webster Cash University of Colorado November 21, 2008

2. NWO Science Telescope 25 Aug 2008 2 Where Next with Space Missions for Exoplanets? There Has Been Stunning Progress in Study of Exoplanets –It takes 10 to 20 years to launch a space observatory –14 years ago this field didn’t exist –where will it be in 20 years with or without space???? A Space Exoplanet Mission Must Have A –Dramatic Leap In Sensitivity and Inner Working Angle –High Quality Spectroscopy –Capability WAAAAAY Beyond What We have Seen So Far Otherwise the Mission Will Rendered Mundane In Short We Need High Quality Spectroscopy of Earth-twins –And broad capability to study planetary systems in detail –Anything less would be a gamble

3. NWO Science Telescope 25 Aug 2008 3 NWO Team Membership: Organizations, Roles and Leads Team consist of 43 active members –9 organizations are participating Additional involvement is provided from each organization and includes technical area experts and graduate/undergraduate students Organizations, Roles and Leads: –Colorado University: PI, Science, Optical Design, and Systems Analysis: Webster Cash –Northrop Grumman: Deputy PI and Starshade Development: Amy Lo –Ball Aerospace Technology Corporation: Telescope Development: Charley Noecker –USNO: Astrometry: Ralph Gaume –NASA GRC: Occulter (Starshade) Propulsion: Scott Benson –KinetX: Mission Design and Navigation: Bobby Williams –GSI: Lead Scientist: Maggie Turnbull –University College of London: Exoplanet Spectra Modeling: Giovanna Tinetti –NASA GSFC: Study Management: Kate Hartman

4. NWO Science Telescope 25 Aug 2008 4 Stars are very bright and their glare makes it difficult to see fainter objects near them

5. NWO Science Telescope 25 Aug 2008 5 New Worlds Observer

6. NWO Science Telescope 25 Aug 2008 6 New Worlds Observer

7. NWO Science Telescope 25 Aug 2008 7 Fly the Telescope into the Shadow

8. NWO Science Telescope 25 Aug 2008 8 Dropping It In Note: No Outer Working Angle

9. NWO Science Telescope 25 Aug 2008 9 Extinguishing The Spot of Arago I Stand on the Spot of Arago and Explain How to Remove the Spot of Arago Occulters Have Very Poor Diffraction Performance –The 1818 Prediction of Fresnel led to the famous episode of: –Spot of Arago (variously Poission’s Spot) –Occulters Often Concentrate Light! Must satisfy Fresnel Equation, Not Just the Fraunhoffer Equation Must Create a Zone That Is: –Deep Below 10 -10 diffraction –Wide A couple meters minimum –Broad Suppress across at least one octave of spectrum Must Be Practical –Binary Non-transmitting to avoid scatter –Size Below 150m Diameter –Tolerance Insensitive to microscopic errors

10. NWO Science Telescope 25 Aug 2008 10 NWO has an Opaque Starshade Opaque Starshade Offset Hypergaussian function Apodization Function Apodizing Function Radius Transmission Parameter Occulter inner radiusa Petal 1/e lengthb Hypergaussian ordern Distance to telescopez Number of petalsP

11. NWO Science Telescope 25 Aug 2008 11 Performance A 50m diameter occulter at 80,000km can reveal Earths at over 20pc

12. NWO Science Telescope 25 Aug 2008 12 Shadow of 16 Petal Mask Linear Log

13. NWO Science Telescope 25 Aug 2008 13 Target Stars: Exo-zodiacal Light From P. Oakley 1.5m 2.4m 4m 10m 4m Case

14. NWO Science Telescope 25 Aug 2008 14 Map Planetary Systems Prime Goal is Exploration of the Solar Neighborhood NWO will allow us to make maps of over 100 nearby planetary systems from the habitable zone outward Detect and classify all major planets Jupiter Saturn Uranus Neptune Zodiacal Light Galaxies 10 arcseconds

15. NWO Science Telescope 25 Aug 2008 15 Study Exoplanets NWO will perform spectroscopy of discovered planets This will reveal their true natures O2O2 H2OH2O CH 4 NH 3

16. NWO Science Telescope 25 Aug 2008 16 Four Color Photometry – Molecules!!

17. NWO Science Telescope 25 Aug 2008 17 Find Earth-like Planets NWO can look close enough to the central star to see Earth twins NWO can find more Earths than any other approach NWO can separate barren rocks from water worlds Need best completeness diagram here

18. NWO Science Telescope 25 Aug 2008 18 Search for Life NWO can do detailed spectroscopy of Earth-like planets –Resolution in the 100 to 1000 range Can easily detect water in the atmosphere Can see surface features as the planet rotates Can detect the key biomarkers

19. NWO Science Telescope 25 Aug 2008 19 NWO Allows Ample time for General Astrophysics While starshade retargets, telescope is free for general astrophysics –At least 50% of telescope time is devoted to general astrophysics –Telescope can see within 50 degrees of sun –Capable of weeks of continuous integration –Telescope operation similar to JWST Scheduling & ops by STScI or equiv. HubbleNWO Instantaneous sky~50%~80% Continuous sky~20%~35%

20. NWO Science Telescope 25 Aug 2008 20 Starshade Critical Technology Enabling Technologies Precision Shape Control Maintain edge position Maintain structure shape Precision Deployment Minimize jitter Maintain petal location Opaque Membrane Maintain opacity Lightweight 2 Axes Formation Flying Maintain 1m alignment Minimize jitter Enhancing Technologies Solar Electric Propulsion NEXT engine Increase observable targets Reduce propellant mass Lightweight S/C Structures Increase observable targets Reduce overall mass Thin Edge Treatment Maintain edge stability Minimize stray light

21. NWO Science Telescope 25 Aug 2008 21 Science Goals Completely Map the Nearby Stellar Systems Catalogue All Major Planets and Belts –Classify Each – (Develop Classification Schemes!) –Measure Approximate Orbit of Each Spectroscopically Study the Most Interesting Planets Find Water Planets Search for Life Watch Planetary Systems Forming General Astrophysics with a True Hubble Follow-on

22. NWO Science Telescope 25 Aug 2008 22 Detect and Study ExoZodis Orbiting dust scatters starlight an cause “exozodiacal light” The exozodi can be strong enough to obscure the planets We currently know NOTHING of the nature of exozodis Knowledge of Exozodi is key to the direct detection of exoplanets NWO can measure hundreds of such systems NWO can detect planets despite high levels of exozodi

23. NWO Science Telescope 25 Aug 2008 23 Confusion from dust structure −“Is that a planet or a dust clump?” −Can we tell by its color before wasting time on a spectrum? Greaves et al. (2005) Epsilon Eridani Other Exozodi Issues Maybe … −Solar System zodi has red scattered light color −Known debris disks show red, grey, & blue colors AU Mic Blue HD 92945 Neutral Beta Pic Red

24. NWO Science Telescope 25 Aug 2008 24 Target Stars: Exposure Times i = 60˚ From A. Roberge

25. NWO Science Telescope 25 Aug 2008 25 Target Stars: Habitable Zones 50 mas IWA From M. C. Turnbull

26. NWO Science Telescope 25 Aug 2008 26 NWO Detection Space Target Stars: Habitable Zones From M. C. Turnbull

27. NWO Science Telescope 25 Aug 2008 27 Characterizing the Planet Turnbull et al. (2006) –Very strong H 2 O signature, like Earth –H 2 O + (surface temp or planet size or orbit) How to know it’s “habitable”? “Habitability” = liquid water on surface Spectrum mostly shows atmosphere

28. NWO Science Telescope 25 Aug 2008 28 Characterizing Planets: Spectroscopy NWO Karkoschka et al. 1998

29. NWO Science Telescope 25 Aug 2008 29 Characterizing Planets: Photometric Variability From P. Oakley

30. NWO Science Telescope 25 Aug 2008 30 The Starshade is Adaptable StarshadeTelescopePrimary Science 15 m1 mExo-zodi mapper 25 m1.5 mOuter Planet imager 50 m4 mTPF + Characterization 100 m10 mLifefinder N x 70 mN x 4 mPlanet Imager Increasing Resolution The starshade offers a scalable technology NWO Can also work with existing telescopes such as JWST