PMH-131 Jan. 2000

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

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

PMH-431 Jan 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.

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

PMH-631 Jan Fizeau Interferometry Collector 1Collector 2

PMH-731 Jan 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

PMH-831 Jan 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.

PMH-931 Jan 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)

PMH-1031 Jan 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.

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

PMH-1231 Jan 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

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

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

PMH-1531 Jan The Bracewell Infrared Nulling Cryostat

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

PMH-1731 Jan BLINC’s First Year

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

PMH-1931 Jan 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

PMH-2031 Jan 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.

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

PMH-2231 Jan Telescope Nulling

PMH-2331 Jan Commissioning run of MIRAC- BLINC, June 10-17, 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

PMH-2431 Jan 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

PMH-2531 Jan 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

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

PMH-2731 Jan IRC Constructive -- Destructive = Point Source Point source in IRC 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

PMH-2831 Jan IRC arcsec N E 11.7 μm 8.8 μm nulled image constructive - null

PMH-2931 Jan 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

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

PMH-3131 Jan 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.

PMH-3231 Jan Nulling Sensitivity

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

PMH-3431 Jan 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 )

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

PMH-3631 Jan 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

PMH-3731 Jan 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 × × × × × × × × × ×10 -5

PMH-3831 Jan 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

PMH-3931 Jan 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

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

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