Direct Imaging and Spectroscopy of nearby Habitable planets with ground-based ELTs Olivier Guyon University of Arizona Astrobiology Center, National Institutes for Natural Sciences (NINS) Subaru Telescope, National Astronomical Observatory of Japan, National Institutes for Natural Sciences (NINS) JAXA Nov 2, 2016 Extreme AO systems (superAO+coronagraph) myths 2 Extreme AO myth #1 ExAO = “Extremely complicated/costly AO” 3 Extreme AO myth #1 ExAO = “Extremely complicated/costly AO” → ExAO is in many respects simpler than other AO systems: - bright on-axis natural guide star (no lasers, easiest configuration for cophasing segments) - zero field of view system (small optics, single DM OK) 4 Extreme AO myth #2 High contrast imaging is all about achieving super low wavefront error → It's all about SR, more actuators, faster loops 5 Extreme AO myth #2 High contrast imaging is all about achieving super low wavefront error → It's all about SR, more actuators, faster loops ExAO is not about making the star's image sharper.. it is about making sure no uncalibrated starlight falls on the exoplanet. In ExAO, the number of actuators in the DM defines the field of view, not the contrast 6 Extreme AO myth #3 High performance coronagraphs don't work on segmented apertures… especially on GMT 7 Extreme AO myth #3 High performance coronagraphs don't work on segmented apertures… especially on GMT → Nothing fundamental about segmented apertures: some high performance coronagraph option(s) don't care about pupil shape and are already working in the lab 8 Extreme AO myth #4 Ground-based telescopes will only ever image giant (Jupiter-like) planets. Directly imaging habitable planets will require a space telescope. 9 Extreme AO myth #4 Ground-based telescopes will only ever image giant (Jupiter-like) planets. Directly imaging habitable planets will require a space telescope. New generation of Extremely Large Telescopes (ELTs) + key technologies will directly image Earth-size planets around nearby low- luminosity stars 10 Extreme AO myth #5 ExAO people have no clue what they are doing. They change their mind about what coronagraph or wavefront sensor to use every two years. Vector Self-coherent PIAA vortex camera coronagraph Photon counting IfU 11 Extreme AO myth #5 ExAO people have no clue what they are doing. They change their mind about what coronagraph or wavefront sensor to use every two years. → ExAO instrument with flexible evolutionary path has a lot of value Develop, iterate & prototype on 5-10m, telescopes → quickly move to ELTs 12 Accessible from Southern Site (Cerro Amazones) Accessible from Northern Site (Mauna Kea) Star Temperature [K] 40 Eri A/B/C A Luyten's star Teegarden's star Tau Ceti YZ Ceti Procyon A/B DX F EZ Aquarii ABC Eps Eri AX Mic Cancri 61 Cyg Ross 154 Kapteyn's Ross 128 A/B star Sirius Lacaille Gliese 15 A&B A/B Gliese 9352 CN G 1061 Leonis Ross 248 Eps Indi UV & BL Ceti Gliese 440 Lalande Barnard's 21185 SRC 1843-6537 Gliese star 725 A/B K α Cen M SOUTH system NORTH Requires source to transit at >30deg elevation above horizon Habitable Zones within 5 pc (16 ly): Astrometry and RV Signal Amplitudes for Earth Analogs Star Temperature [K] Detection limit Sirius for ground-based optical RV α Cen A Expected detection F, G, K stars limit for space astrometry (NEAT, α Cen B THEIA, STEP) F, G, K stars Procyon A Proxima Cen Eps Eri Barnard's star CN Leonis Circle diameter is proportional to 1/distance Circle color indicates stellar temperature (see scale right of figure) Astrometry and RV amplitudes are given for an Earth analog receiving the same stellar flux as Earth receives from Sun (reflected light) Expected detection limit for near-IR RV surveys (SPIROU, IRD + others) M-type stars Habitable Zones within 5 pc (16 ly) Star Temperature [K] 1 Gliese 1245 A LP944- 2 Gliese 1245 B SRC 1845-6357 A 020 3 Gliese 674 DEN1048-3956 4 Gliese 440 (white dwarf) Wolf 424 5 Gliese 876 (massive planets in/near HZ) A A 6 Gliese 1002 Van Maanen's Star LHS 292 7 Gliese 3618 DX Cnc Ross 614 B 8 Gliese 412 A Teegarden's star 9 Gliese 412 B TZ Arietis 4 9 10 AD Leonis CN Leonis 11 Gliese 832 YZ Ceti Wolf 424 2 UV GJ 1061 B 7 Ceti EZ Aqu A,B & LHS380 6 Proxima Cen BL Ceti RossC 248 1 Gl15 B Kruger 60 B Ross 154 Barnard's Ross 128 Ross 614 A 40 Eri C Star Kapteyn's F 40 Eri B Procyon B star Wolf Gl725 B 1061 3 5 Gl725 A Gliese Lalande 21185 Gl15 A 1 8 Lacaille 9352 Kruger 60 10 Sirius B A 11 Luyten's star Gliese 687 AX Mic 61 Cyg G A Groombridge 61 Cyg 1618 B Eps Indi Eps Eri α Cen B 40 Eri A Tau Ceti K α Cen A Procyon A Sirius M Circle diameter indicates angular size of habitable zone Circle color indicates stellar temperature (see scale right of figure) Contrast is given for an Earth analog receiving the same stellar flux as Earth receives from Sun (reflected light) Spectroscopic characterization of Earth-sized planets with ELTs 1 λ/D 1 λ/D 1 λ/D Around about 50 stars (M type), λ=1600nm λ=1600nm λ=10000nm rocky planets in habitable zone D = 30m D = 8m D = 30m could be imaged and their spectra acquired [ assumes 1e-8 contrast limit, 1 l/D IWA ] K-type and nearest G-type stars M-type stars are more challenging, but could be accessible if raw contrast can be pushed to ~1e-7 (models tell us it's possible) Thermal emission from habitable planets around nearby A, F, G log10 contrast type stars is detectable with ELTs K-type stars G-type stars 1 Re rocky planets in HZ for stars within 30pc (6041 stars) F-type stars Angular separation (log10 arcsec) Habitable Zones within 5 pc (16 ly) Star Temperature [K] 1 Gliese 1245 A LP944- 2 Gliese 1245 B SRC 1845-6357 A 020 3 Gliese 674 DEN1048-3956 4 Gliese 440 (white dwarf) Wolf 424 5 Gliese 876 (massive planets in/near HZ) A A 6 Gliese 1002 Van Maanen's Star LHS 292 7 Gliese 3618 DX Cnc Ross 614 B 8 Gliese 412 A Teegarden's star 9 Gliese 412 B TZ Arietis 4 9 10 AD Leonis CN Leonis 11 Gliese 832 YZ Ceti Wolf 424 2 UV GJ 1061 B 7 Ceti EZ Aqu A,B & LHS380 6 Proxima Cen BL Ceti RossC 248 1 Gl15 B Kruger 60 B Radial Velocity Ross 154 Barnard's Ross 128 (near-IR) Ross 614 A 40 Eri C Star Kapteyn's F 40 Eri B Procyon B star Wolf ELT imaging Gl725 B 1061 3 5 (near-IR) Gl725 A Gliese Lalande 21185 Gl15 A 1 8 Lacaille 9352 Kruger 60 10 Sirius B A 11 Luyten's star Gliese 687 AX Mic Space 61 Cyg G A Groombridge 61 Cyg astrometry 1618 B Eps Indi Eps Eri α Cen B 40 Eri A Tau Ceti K ELT imaging α Cen A (thermal-IR) Procyon A Sirius M Circle diameter indicates angular size of habitable zone Circle color indicates stellar temperature (see scale right of figure) Contrast is given for an Earth analog receiving the same stellar flux as Earth receives from Sun (reflected light) The Subaru Coronagraphic Extreme-AO (SCExAO) instrument ● Flexible high contrast imaging platform ● Meant to evolve to TMT instrument and validate key technologies required for direct imaging and spectroscopy of habitable exoplanets Core system funded by Japan from multiple grants, current JSPS grant “Imaging Habitable zone Planets with Subaru Telescope and TMT” focused on wavefront control (includes MKIDs camera for speckle control + efficient WFS/C) Modules/instruments funded by Japan + international partners: - IFS funded by Japan, built by Princeton Univ - MKIDs funded by Japan, built by UCSC - SAPHIRA camera provided by UH - VAMPIRES instrument funded and built by Australia - FIRST instrument funded and built by Europe 18 SCExAO near-IR bench, End 2016 HiCIAO or MKIDS Near-IR InGaAs cameras → to be replaced with EI technology CHARIS Near-IR nuller SAPHIRA Low latency WFC in visible light at the diffraction limit sensitivity 2000 actuators MEMs DM running at 3.6 kHz deep depletion EMCCD Non-modulated pyramid WFS cannot rely on slope computations → full WFS image is multiplied by control matrix One of two GPU chassis Now delivering 90% SR in H Recent upgrade allows 3.6kHz loop operation with zonal and modal reconstruction → low-latency control → modal reconstruction for predictive / LQG control (under development) SCExAO uses 30,000 cores running @1.3GHz ~0.5 Hz ~2 kHz Extreme-AO CORONAGRAPHIC LOOP LOW ORDER LOOP Near-IR camera High speed pyramid 10-200 Hz wavefront sensor Measures low-order Measures aberrations aberrations 800 – 2500 nm 3.7 kHz (rejected by coronagraph) MKIDs camera m n 0 0 800 – 1350 nm 8 coronagraph Measures residual < system starlight removes starlight Facility Adaptive 2000 actuator >800nm SPECKLE Optics system Deformable mirror CONTROL LOOP Sharpens image CHARIS spectrograph Visible light instruments Near-IR instruments Exoplanet spectra VAMPIRES, FIRST, RHEA Nuller, HiCIAO, IRD Slow speckle calibration Nominal ELT ExAO system architecture INSTRUMENTATION High-res spectroscopy can Visible light Near-IR detect molecular species and Imaging, Imaging, separate speckles from planet Thermal IR spectroscopy, spectroscopy, spectra Imaging & polarimetry, polarimetry spectroscopy coronagraphy Woofer DM, Tweeter DM Speckle control Low-IWA afterburner WFS ~2 kHz speed 10kHz response coronagraph 120 x 120 actuators 50x50 actuators High efficiency Delivers visible Provides high Speed ~kHz diffraction-limited PSF contrast Photon-counting to visible WFS detector > focus WFS pointing Coronagraphic Low-order WFS uses light rejected by TT, focus? coronagraph → catches aberrations BEFORE they hurt contrast → stellar leakage derived from Visible / nearIR light low- telemetry latency WFS Diffraction limited sensitivity Coronagraph System Requirements : - IWA near 1 l/D - high throughput (>~50% @ 2 l/D) - ~1e-6 raw contrast - resilient against stellar angular size (ELTs partially resolve stars) Current status: At least two approaches meet requirements: Vortex, PIAACMC Performance demonstrated in lab on centrally obscured pupil (WFIRST) in visible light.