1. PMH-131 Jan. 2000

2. PMH-231 Jan. 2000 Nulling Interferometry for Studying Other Planetary Systems: Techniques and Observations Phil Hinz PhD Thesis Defense Wednesday Jan. 31, 2000

3. PMH-331 Jan. 2000 Challenges of Finding Planets Mass of Jupiter is 10 -3 M sun Giant Planet Brightness is: 10 -9 L sun in visible 10 -6 L sun in IR Dust Disk is 10 -4 L sun in IR Direct Detection Requirements:large aperture telescopes wavefront correction suppression of starlight Need instrumental development to make scientific progess.

4. PMH-431 Jan. 2000 Advantages of Direct Detection We want to see planets not just infer their existence. Direct emission from planets can tell us about their chemical make-up, temperature, etc... We can learn more about it. Wide orbit planets such as Jupiter or Saturn require prohibitive time baselines for Doppler velocity detection.

5. PMH-531 Jan. 2000 Bracewell Interferometry Collector 1 Collector 2 Semi-transparent mirror left outputright output ΔΦ Stellar wavefront Companion wavefront

6. PMH-631 Jan. 2000 Fizeau Interferometry Collector 1Collector 2

7. PMH-731 Jan. 2000 Resolving Faint Companions Fizeau interferometry is well –suited for high spatial resulotion studies Pupil-plane interferometry is well-suited for suppression of starlight. Star Companion (1% of star brightness) Star+Companion

8. PMH-831 Jan. 2000 Nulling Measurements Source Orientation 1 Orientation 22 PSF of single element Nulling interferometry measures the total flux transmitted by the interference pattern of the two elements, convolved with the PSF of a single element.

9. PMH-931 Jan. 2000 Subtlety 1: Chromaticity of Null Fraction of light remaining in nulled out put is given by where Level of suppression is good over only a narrow bandwidth. Three fixes: Rotate one beam 180 degrees (Shao and Colavita) Send one beam through focus (Gay and Rabbia) Balance dispersion in air by dispersion in glass (Angel, Burge and Woolf) Dispersion Compensation allows out-of band light to be used to sense phase (Angel and Woolf 1997)

10. PMH-1031 Jan. 2000 Subtlety 2: True Image Formation In Bracewell’s concept the beams form images which are mirror versions of one another. Rotation nulls create images which are rotated versions of one another. It is only possible to create a true image of the field using dispersion compensation for the suppression and an interferometer which has an equal number of reflections in each beam.

11. PMH-1131 Jan. 2000 First Telescope Demonstration of Nulling Nulling at the MMT Nature 1998; 395, 251. Ambient Temperature Optics

12. PMH-1231 Jan. 2000 Beam-splitter design Requirements:Equal reflection and transmission at nulling wavelength Equal reflection and transmission at phasing wavelength Symmetric design (to avoid chromatic phase shifts) Substrate suitable for dispersion compensation. Design: ZnSe substrate λ 0 /4 air gap difference in substrate thickness of 39 μm

13. PMH-1331 Jan. 2000 Phase Compensation of Null Phase (waves) Intensity Wavelength (μm)

14. PMH-1431 Jan. 2000 Beam-splitter Performance Reflection Intensity Wavelength (μm) Phase difference (waves) phase sensing passband Nulling passband

15. PMH-1531 Jan. 2000 The Bracewell Infrared Nulling Cryostat

16. PMH-1631 Jan. 2000 telescope beam reimaging ellipsoid beam-splitter 2 μm detector 10 micron detector imaging “channel” nulling “channel” Mechanical Design

17. PMH-1731 Jan. 2000 BLINC’s First Year

18. PMH-1831 Jan. 2000 Laboratory Setup HeNe laser Dichroic CO 2 laser Ball mirror “Telescope” mirrorFold mirror Interferometer Infrared Camera

19. PMH-1931 Jan. 2000 Laboratory Results CO 2 laser source yielded a null with an integrated flux of 3x10 -4 Entire Airy pattern along with the scattered light disappears in nulled image. 0.5 s exposure images at 10.6 μm

20. PMH-2031 Jan. 2000 path-length (microns) Intensity Laboratory Results II 50% bandwidth causes adjacent nulls to be significantly > 0. Relative depth of the adjacent nulls determines achromaticity of central null.

21. PMH-2131 Jan. 2000 Constructive image Scanning pathlength 0.5% of peak 2% of peak White=5% of peak Laboratory Null

22. PMH-2231 Jan. 2000 Telescope Nulling

23. PMH-2331 Jan. 2000 Commissioning run of MIRAC- BLINC, June 10-17, 2000. Aligned and phased the interferometer during the first night of observing Observed AGB stars, several Herbig Ae stars, and several main-sequence stars. Observed again in October, but weather was poor. Observing at the MMT

24. PMH-2431 Jan. 2000 Pupil Alignment of BLINC Right beam outer edge of primary Left beam outer edge of primary Left beam secondary obscuration Right beam secondary obscuration Pupil stop size for nulling observations

25. PMH-2531 Jan. 2000 Dust outflow around Antares α Boo α Sco constructive destructive Best nulls of α Boo have a peak ratio of 3%. The integrated light is 6% of the constructive image. The nulled images of α Sco are 25% of the constructive images. Suppression of the starlight allows us to form direct images of the dust outflow around the star

26. PMH-2631 Jan. 2000 Antares baseline vertical N E baseline horizontal 5 arcsec

27. PMH-2731 Jan. 2000 IRC+10216 Constructive -- Destructive = Point Source Point source in IRC+10216 is faint compared to its extended dust nebula. By modulating the point source we can determine its contribution as well as its registration to the nebula. This has been a source of confusion for IRC+10216

28. PMH-2831 Jan. 2000 IRC+10216 1 arcsec N E 11.7 μm 8.8 μm nulled image constructive - null

29. PMH-2931 Jan. 2000 Herbig Ae/Be stars Chiang and Goldreich (1997) have created models to explain the spectral energy distribution of T Tauri stars and Herbig Ae/Be stars. Disk would be only 0.2” across, so too small for direct imaging detection, but would not have a null of < 40\%. R*R* r τ = 1 τ = α α

30. PMH-3031 Jan. 2000 Herbig Ae/Be stars Three nearby Herbig Ae stars observed with BLINC, June 2000. stard (pc) Expected Residual Flux Measured Residual Flux Position Angle HD15019315041%0±5%97 º HD16329612249%-1 ±7% 3 ±3% 94 º 10 º HD17921824041%3 ±3% 1 ±3% 162 º 87 º Indicates region of emission is smaller than predicted by model.

31. PMH-3131 Jan. 2000 Main Sequence Stars Two nearby main sequence stars observed with BLINC, June 2000: Vega and Altair. StarNullResidual Flux WavelengthPosition Angle Vega14 ±3%1 ±4% 11.7 μm 133 º Vega13 ±3%0 ±4%10.3 μm135 º Altair8 ±4%-5 ±5%10.3 μm97º Using the DIRBE model for our solar zodiacal cloud (Kelsall et al. 1998), a limit of approximately 3700 times solar level for Vega and 2500 times solar level for Altair. IRAS photometric limits at 12 μm are approximately 1800 times solar level for both stars.

32. PMH-3231 Jan. 2000 Nulling Sensitivity

33. PMH-3331 Jan. 2000 Depth of Null:Star Diameter arcseconds transmission star diameter

34. PMH-3431 Jan. 2000 MMT Nulling Error Budget Star diameter at 10 pc Star leak At 11 μm G2V star 1.6x10 -6 Chromatic phase errors Beam-splitter 4.0x10 -6 Chrom. and Pol. Amp. Errors Beam-splitter 3.8x10 -5 Adaptive Optics Spatial Error Temporal Error Atmosphere Fitting error Time lag of system 2.0x10 -4 (1.6x10 -5 ) 1.2x10 -4 (1.70x10 -5 ) Error Source Level Total flux: 3.6x10 -4 (7.7x10 -5 )

35. PMH-3531 Jan. 2000 Expected Sensitivity Wavelength (μm) photons/s/m 2 /μm/arcsec 2 Sky Background Telescope Background L'L' M N MMTLBT 10-12.2 μm66045 M band19021 L‘ band182.1

36. PMH-3631 Jan. 2000 MMT Dust Limits for stars at 10 pc Cloud density (zodis) Flux in nulled output of MMT (μJy) dust around an A0 star F0 star G0 star K0 star M0 star MMT detection limit

37. PMH-3731 Jan. 2000 MMT zodiacal dust detection The short baseline of the MMT gives it 13 times better suppression of a star than LBT and 450 times better than Keck. StarSpec. TypeDistance (pc) Dust Limit (vs. solar) Star Leak Sirius ε Eri 61 Cyg A 61 Cyg B α Cmi τ Ceti Gl380 ω 2 Eri 70 Oph Altair A1V K2V K5Ve K7Ve F5IV-V G8Vp K2Ve K1Ve K0Ve A7IV-V 2.64 3.22 3.48 3.50 3.65 4.87 5.04 5.09 5.14 0.1 10 29 50 0.9 7 34 29 23 0.6 9.4×10 -5 1.0×10 -5 7.0×10 -6 6.0×10 -6 2.3×10 -5 9.5×10 -6 4.4×10 -6 4.3×10 -6 4.6×10 -6 1.6×10 -5

38. PMH-3831 Jan. 2000 LBT dust limits for stars at 10 pc Cloud density (zodis) Flux in nulled output of LBT (μJy) dust around an A0 star F0 star G0 star K0 star M0 star LBT detection limit

39. PMH-3931 Jan. 2000 Planet Limits age (Gyr) Flux of 5 M J planet (μJy) MMT L' band limit MMT M band limit MMT 11 μm limit L' band flux N band flux M band flux of 5 M J planet

40. PMH-4031 Jan. 2000 Planet Limits mass (M J ) L' band flux (μJy) LBT limit MMT limit 5 Gyr flux of 0.5 Gyr old planet 1 Gyr

41. PMH-4131 Jan. 2000 Phase space of Direct Detection Separation (AU) Mass (Jupiter masses) MMT limit LBT limit Radial velocity limit