Detailed Spectroscopy of Exoplanets with The New Worlds Observer

1. Detailed Spectroscopy of Exoplanets withThe New Worlds Observer Webster Cash University of Colorado November 21, 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 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. Stars are very bright and their glare makes it difficult to see fainter objects near them

5. New Worlds Observer

6. New Worlds Observer

7. Fly the Telescope into the Shadow

8. Dropping It In Note: No Outer Working Angle

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 has an Opaque Starshade Transmission Radius • Apodizing Function Apodization Function Offset Hypergaussian function • Opaque Starshade

11. Performance A 50m diameter occulter at 80,000km can reveal Earths at over 20pc

12. Shadow of 16 Petal Mask Log Linear

13. Target Stars: Exo-zodiacal Light 4m Case From P. Oakley 10m 4m 2.4m 1.5m

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 Uranus Galaxies Zodiacal Light Jupiter Saturn Neptune 10 arcseconds

15. Study Exoplanets H2O O2 • NWO will perform spectroscopy of discovered planets • This will reveal their true natures CH4 NH3

16. Four Color Photometry – Molecules!!

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. 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 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.

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

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. 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. Other Exozodi Issues HD 92945 Neutral AU Mic Blue Beta Pic Red Epsilon Eridani • 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) • Maybe … • Solar System zodi has red scattered light color • Known debris disks show red, grey, & blue colors

24. Target Stars: Exposure Times i = 60˚ From A. Roberge

25. Target Stars: Habitable Zones 50 mas IWA From M. C. Turnbull

26. Target Stars: Habitable Zones NWO Detection Space From M. C. Turnbull

27. Characterizing the Planet • “Habitability” = liquid water on surface • Spectrum mostly shows atmosphere Turnbull et al. (2006) • How to know it’s “habitable”? • Very strong H2O signature, like Earth • H2O + (surface temp or planet size or orbit)

28. Characterizing Planets: Spectroscopy NWO Karkoschka et al. 1998

29. Characterizing Planets: Photometric Variability From P. Oakley

30. The Starshade is Adaptable Increasing Resolution NWO Can also work with existing telescopes such as JWST The starshade offers a scalable technology