1. Vacuum, Extreme Radial Velocity Experiment: VERVE An instrument for ultra-precise radial velocity measurements J. Kent Wallace (JPL) 28 July 2015

2. Fellow Contributors Michael Randolph, LCHS Rebecca Jensen-Clem, CIT Gautam Vasisht, JPL Phil Muirhead, BU Lynne Hillenbrand, CIT Erik Hovland, JPL Richard Dekany, CIT 2

3. Outline 1.Radial Velocity Measurement Overview 2.Instrument Description 3.Preliminary Data 4.Performance Predictions 5.Conclusion 3

4. Outline 1.Radial Velocity Measurement Overview 2.Instrument Description 3.Preliminary Data 4.Performance Predictions 5.Conclusion 4

5. Radial Velocity Measurement Overview 5 Traditional Spectroscopy Traditional Spectroscopy 1 1 Intensity Wavelength Iodine spectral reference Grating spectrograph The Goal ΔRV=10cm/s Δλ = 1x10 -5 Å The Requirement: Δλ = 2x10 -6 Å The State of the Art: 70cm/s

6. Radial Velocity Measurement Overview 6 E xternally D ispersed I nterferometry (EDI) 2 2 spectralfringe.org Scanning Interferometer Time λ Grating spectrograph Absorption lines Moire pattern Interferometer transmission comb Traditional Spectroscopy Traditional Spectroscopy 1 1 Intensity Wavelength Iodine spectral reference Grating spectrograph

7. One Pixel 5499.915499.9555005500.055500.09 Wavelength [Å] Relative Flux 7 Image Credit: Phil Muirhead

8. One Pixel Flux 5499.915499.9555005500.055500.09 Wavelength [Å] Relative Flux Delay Change [μm] 0.00.51.01.52.02.5 8 Image Credit: Phil Muirhead

9. One Pixel Flux 5499.915499.9555005500.055500.09 Wavelength [Å] Relative Flux Flux Delay Change [μm] 0.00.51.01.52.02.5 9 Image Credit: Phil Muirhead

10. One Pixel Flux 5499.915499.9555005500.055500.09 Wavelength [Å] Relative Flux Flux Delay Change [μm] 0.00.51.01.52.02.5 10 Image Credit: Phil Muirhead

11. One Pixel Flux 5499.915499.9555005500.055500.09 Wavelength [Å] Relative Flux Flux Delay Change [μm] 0.00.51.01.52.02.5 11 Image Credit: Phil Muirhead

12. One Pixel Flux 5499.915499.9555005500.055500.09 Wavelength [Å] Relative Flux Flux Delay Change [μm] 0.00.51.01.52.02.5 12 Image Credit: Phil Muirhead

13. One Pixel Flux 5499.915499.9555005500.055500.09 Wavelength [Å] Relative Flux Flux Delay Change [μm] 0.00.51.01.52.02.5 13 Image Credit: Phil Muirhead

14. One Pixel Flux 5499.915499.9555005500.055500.09 Wavelength [Å] Relative Flux Flux Delay Change [μm] 0.00.51.01.52.02.5 14 Image Credit: Phil Muirhead

15. One Pixel Flux 5499.915499.9555005500.055500.09 Wavelength [Å] Relative Flux Flux Delay Change [μm] 0.00.51.01.52.02.5 15 Image Credit: Phil Muirhead

16. One Pixel Flux 5499.915499.9555005500.055500.09 Wavelength [Å] Relative Flux Flux Delay Change [μm] 0.00.51.01.52.02.5 16 Image Credit: Phil Muirhead

17. One Pixel Flux 5499.915499.9555005500.055500.09 Wavelength [Å] Relative Flux Flux Delay Change [μm] 0.00.51.01.52.02.5 Image Credit: Phil Muirhead

18. One Pixel Flux 5499.915499.9555005500.055500.09 Wavelength [Å] Relative Flux Flux Delay Change [μm] 0.00.51.01.52.02.5 18 Image Credit: Phil Muirhead

19. One Pixel Flux 5499.915499.9555005500.055500.09 Wavelength [Å] Relative Flux Flux Delay Change [μm] 0.00.51.01.52.02.5 19 Image Credit: Phil Muirhead

20. 1 km/s Doppler Shift One Pixel Flux 5499.915499.9555005500.055500.09 Wavelength [Å] Relative Flux Flux Delay Change [μm] 0.00.51.01.52.02.5 20 Image Credit: Phil Muirhead

21. Outline 1.Radial Velocity Measurement Overview 2.Instrument Description 3.Preliminary Data 4.Performance Predictions 5.Conclusion 21

22. Instrument Description 22 BS2 Grating Fiber-Fed OAP Lens Imaging Array Fold Mirror BS1 Prism Fold Mirror PZT Flexure Stage

23. Instrument Description 23 BS2 Grating Fiber-Fed OAP Lens Fold Mirror BS1 Prism Fold Mirror PZT Flexure Stage Imaging Array

24. Outline 1.Radial Velocity Measurement Overview 2.Instrument Description 3.Preliminary Data 4.Performance Predictions 5.Conclusion 24

25. Preliminary Data 25

26. Preliminary Data

37. Outline 1.Radial Velocity Measurement Overview 2.Instrument Description 3.Preliminary Data 4.Performance Predictions 5.Conclusion 37

38. Performance Predictions 38 The Palomar 200” telescope would take about 0.075 seconds to reach an SNR=8 resolution element, given the assumptions in the above tables. For 425 scans, each with 200 0.075 sec phase steps, the 200” telescope would require about 1.8 hours to reach a radial velocity precision of 10 cm/sec.

39. Outline 1.Radial Velocity Measurement Overview 2.Instrument Description 3.Preliminary Data 4.Performance Predictions 5.Conclusion 39

40. Conclusion Radial velocity precision of 10 cm/sec appears achievable with externally dispersed interferometry. We are developing instrumentation to demonstrate this. Low-noise detectors are critical to demonstrating this new instrument. 40