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Exoplanet Exploration Program, Planet Detection Test-bed: Latest results of planet light detection in the presence of starlight. Andrew J. Booth, Stefan R. Martin, Frank Loya, Jet Propulsion Laboratory, California Institute of technology. Summary. Test-bed goals
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Exoplanet Exploration Program, Planet Detection Test-bed: Latest results of planet light detection in the presence of starlight Andrew J. Booth, Stefan R. Martin, Frank Loya, Jet Propulsion Laboratory, California Institute of technology A.J.Booth et al., Planet Detection Testbed
Summary • Test-bed goals • Introduction to the Planet Detection test-bed (PDT) • Additions to Test-bed since 2006 • Nulling performance • Planet detections • Future plans A.J.Booth et al., Planet Detection Testbed
Test-bed Goals • Lab simulation for a near infrared terrestrial exoplanet characterization mission • 10um, dual nulling interferometer • X-array “Emma”, formation flying • Other testbeds deal with: • formation flying • broadband nulling • PDT emulates 4 beam nulling and cross combining for: • Optical arrangements • Control systems • Planet signal extraction A.J.Booth et al., Planet Detection Testbed
Test-bed Goals • Detect “planet” signal at 106:1 contrast ratio with star with SNR 3 • Stable nulls of 105:1 • Local zodiacal light at ~10-4 of star mean better nulls superfluous • Extra 100:1 contrast ratio below null depth obtained by: • Chopping planet signal - interferometrically • Rotation of array through 360º and averaging A.J.Booth et al., Planet Detection Testbed
Introduction to the PDT π Nuller 1 Cross-combiner Planet source Detector pinholes Star thermal source π Nuller 2 Star laser source A.J.Booth et al., Planet Detection Testbed
Introduction to the PDT • Null starlight • Chop cross combiner optical path from fringe peak on one side of star to fringe peak on other side of star (star at inflection point) • Planet signal is difference in flux on two sides of chop A.J.Booth et al., Planet Detection Testbed
Introduction to PDT A.J.Booth et al., Planet Detection Testbed
Test-bed updates since 2006 Shear detector Shear mirror Tip-tilt detector π nuller Tip-tilt laser source Tip-tilt detector Tip-tilt mirror Star source Shear detector • Closed loop tip-tilt (few 10Hz) and shear (few Hz) servos with detectors working at 850nm A.J.Booth et al., Planet Detection Testbed
Test-bed updates since 2006 π Nuller 1 Cross-combiner Planet source Detector pinholes Star thermal source π Nuller 2 Star laser source • Fringe tracking at ~2.5um, ~1Hz • Star thermal source • Control signal is difference of two beam combiner outputs • One for each nuller and cross combiner • laser metrology tracking at ~1.5um, ~100Hz • Up stream and down stream from beam train mid point A.J.Booth et al., Planet Detection Testbed
Test-bed updates since 2006 • Phase plates • Path matching at nulling and fringe tracking wavelengths • Nullers: • Null at 10um • Fringe signal inflection point at 2.5um • Cross combiner • Chop 10um fringe peak to trough • Chop from 2.5um inflection point to inflection point A.J.Booth et al., Planet Detection Testbed
Test-bed updates since 2006 π Nuller 1 Cross-combiner Planet source Detector pinholes Star thermal source π Nuller 2 Star laser source • Planet input optics with optical path modulation to allow simulation of array rotations A.J.Booth et al., Planet Detection Testbed
Nulling performance • Short term (100s) null depth • Max null depth 1.6×106:1 • Mean null depth 9×105:1 (goal: better than 105:1) • Short term noise due to poor metrology tracking peak shutter A.J.Booth et al., Planet Detection Testbed
Nulling performance peak shutter • Long term null stability • Drift of < few 106:1 over 104s (goal : better than <105:1) A.J.Booth et al., Planet Detection Testbed
Planet Detection • Linear dual Bracewell array configuration • Planet at ~0.1urad from star (~1AU at ~50pc) Time (sec) A.J.Booth et al., Planet Detection Testbed
Planet Detection • Normalized cross correlation of data with templates A.J.Booth et al., Planet Detection Testbed
Simulated Emma Array planet signal • Simulated “Emma” array planet signal • Array ratio 6:1, radius 60m, planet at 0.375urad Normalized planet chopped signal Array Rotation (degrees) A.J.Booth et al., Planet Detection Testbed
Future Plans • Emma array simulations • Broad band nulling from Ar-arc source with dispersed dectection • Will allow further ~10x sensitivity improvement using wavelength fitting of fringe rotation data, allowing planet detection at realistic 107 contrast ratios. A.J.Booth et al., Planet Detection Testbed