PLATO: Estado y perspectivas
PLA netary Transits and Oscillations of stars
J. Miguel Mas-Hesse Centro de Astrobiología (CSIC-INTA) SEA 2010 Sept.17 th , 2010 Introduction
• PLATO: PLA netary Transits and Oscillations of stars
• Planet transit experiment + seismic analysis (stellar oscillations) of host stars. • Ultra-high precision, long, uninterrupted photometric monitoring of very large samples of bright stars: CoRoT - Kepler heritage. • Medium-class candidate mission to the ESA Cosmic Vision programme. • Currently under definition study. In competition with: – Solar Orbiter (almost pre-selected!) – Euclid • Decision to be made by ESA on June 2011.
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 2 Objectives
• To detect and characterize exoplanets of all kinds, including telluric planets in the habitable zone. • To characterize the properties (mass, age,…) of the parent star.
• Combining photometry and radial velocity observations is essential for planet characterization. – stellar photometry: asteroseismology properties of the stars, including their evolutionary state – photometric transits: orbit, radius, inclination – radial velocity follow-up: confirmation, mass planet density, internal structure
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 3 Techniques
153 Transits
3 Transits
0.010%
Photometric transits
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 4 Techniques
Follow up radial velocity observation will be essential to confirm the exoplanet and to derive its mass (i.e., its density).
Planet Separation RV Amp. (AU) (m/s) Jupiter 1 28.4 Neptune 0.1 4.8 Neptune 1 1.5 SuperEarth 0.1 1.4 PLATO SuperEarth 1 0.5 Earth 1 0.1 Kepler
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 5 ESA Cosmic Vision Dec 1 2009 PLATO: PLAnetary Transits and Oscillations of stars 5 Techniques
M =1.36 +/- 0.04 M Age=3.90 +/- 0.4 Gyr
Asteroseismology
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 6 PLATO objectives and products
Identification of planetary systems Characterisation of host stars detection and characterisation + detection and characterisation of planet transits of stellar oscillations
ultra-high precision , high duty cycle , long duration photometric monitoring of large samples of bright stars
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 7 ESA Cosmic Vision Dec 1 2009 PLATO: PLAnetary Transits and Oscillations of stars 7 Noise requirements : transit search ≤ 2.7 x 10 -5 per hr for high S/N transit measurement ≤ 8.0 x 10 -5 per hr for marginal transit detection
1 R ⊕ planet transiting a solar-like star at 1 AU - mean of 3 transits
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 8 ESA Cosmic Vision Dec 1 2009 PLATO: PLAnetary Transits and Oscillations of stars 8 PLATO Goals
Basic science > 20,000 bright (~ m ≤11) requirements V cool dwarfs/subgiants (>F5V&IV): exoplanet transits AND seismic analysis of their host stars AND ultra-high precision RV follow-up
noise < 2.7 10 -5 in 1hr >1,000 very bright >3,000 very bright for 3 years (m V≤8) (m V≤8) exoplanets cool dwarfs/subgiants cool dwarfs/subgiants around bright and nearby stars for 3 years for >5 months
> 250,000 cool dwarfs/subgiants (~ mV≤13) exoplanet transits + RV follow-up
noise < 8.10 -5 in 1hr PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 9 for 3 years The challenge
• Very wide field-of-view (as many stars as possible) and • Large collecting area (photon noise below scientific requirement) and • Very stable environment (any noise source < 1/3 photon noise)
During the assessment phase 3 concepts emerged:
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 10 The options
• Astrium • Thales Alenia – 12 reflective telescopes – 54 refractive telescopes – 14 CCDs per focal plane – 2 CCDs per focal plane
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 11 The PLATO Payload Consortium Concept
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 12 The PPLC Concept
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PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 13 The PPLC Concept
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 14 The PPLC Concept
• Los telescopios se agrupan de manera que sus FoV se solapen:
– La zona central alcanza el máximo de cubrimiento y la máxima precisión fotométrica.
– Las zonas periféricas permiten aumentar el número de estrellas monitorizado.
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 15 The PPLC Concept: Telescopes
• Very compact design – Structure: 4.1 kg – Optics: 6.1 kg – Baffle: 0.5 kg – FPA: 1.3 kg Total: 12.2 kg
• No focusing mechanism – ± 50 µm tolerance – Thermal stability
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 16 The PPLC Concept: Focal Plane Assembly
• Being developed by the Spanish team: CAB + LIDAX • Goals:
– Very high thermomechanical stability – Large detector area – As many pixels as possible – Isolation from the electronics
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 17 The PPLC Concept: Focal Plane Assembly
MASK
CCDs Assembly FPA-TOU INTERFACE RING TOU FLANGE
THERMAL STRAP (4x)
MLI
OPTICAL BENCH FEE Box
THERMAL BUS FEE THERMAL STRAP
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 18 The PPLC Concept: Focal Plane Assembly
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 19 The PPLC Concept: Focal Plane Assembly
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 20 The PPLC Concept: Focal Plane Assembly
FAST FPA / HOT CASE Temperature (pink): assumption Figures include both radiation and conduction paths Positive goes into the FPA/FEE Temperature (blue): result SPACE ITEM FPA FEE DISSIPATION [W] 4x1.4 7.5 TOU* [W] -8.43 0 FEE** [W] 2.36 - FPA** [W] - -2.36 Optical Bench*** [W] 0 0.33 HEATER TOU Thermal Bus** [W] 0 -4.49 Rest of SpaceCraft*** 0.47 -0.98 198 K [W] 0.3W 0.27W 8.16W * Conduction + Radiation ** Only Conduction 201.6-204.5K FPA 5.6W *** Only Radiation 0.17W
224-280K 0.32W 2.36W Radiative link RADIATIVE SHIELD Radiative FLEXCABLES (5mW/K) 0.67W insulation 308-320K 7.5W Mechanical FEE THERMAL BUS conductive link 4.49W 0.33W Mechanical non conductive link 313K OPTICAL BENCH Flex
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 21 The PPLC Concept: Optical bench
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 22 PLATO: CCDs
• 4 x (4.510 x 4.510) CCDs, 18 m x 18 m pixel size • Plate scale: ~14.3 arcsec/px • Focal planes layout.
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 23 PLATO: CCDs
Buttable CCD prototype (E2V)
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 24 End to end simulations
Stellar field PLATO image
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 25 On-board data processing
• Onboard data processing will be one of the hot issues for PLATO
– 4 CCDs per focal plane, > 80 millions pixels read out and processed every 25 s per telescope – ~300.000 objects monitored continuously – Fully automatic onboard photometric extraction procedure – Cosmic ray rejection, recentering, calibration performed onboard. – Coordinated for 30+2 telescopes • Final data have to fit within a telemetry rate of ~1.2 Mbps
• The DPUs will be developed by the Spanish consortium (CAB+IAA+Companies)
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 26 On-board data processing architecture 4510 px 4510 4510 px 4510
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 27 On-board data processing architecture 4510 px 4510
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 28 On-board data processing architecture 4510 px 4510 4510 px 4510 4510 px 4510 4510 px 4510
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 29 On-board data processing architecture
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 30 PLATO: Mission operations
• Orbital Geometry: – Spacecraft orbiting around L2
• Observation strategy: – Inertial pointing on 2 fields, 3+2 years, 1 year step and stare
– Rotation of the S/C by 90 deg every 3 months.
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 31 PLATO: Mission operations
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 32 PLATO: Mission concept
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 33 PLATO: next steps
• An Announcement of Opportunity was issued by ESA in July 2010 for the provision of the payload. – The proposal is being prepared now. Deadline Oct. 30th.
• Selection for the Implementation Phase will take place in June-November 2011.
• PLATO will compete directly with Euclid (dark energy mission)
• There is a strong European support, and no technological development required – PLATO is based on “simple” individual telescopes with standard CCDs.
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 34 PLATO: next steps
• Contribution by the Spanish PLATO group:
– The Focal Plane Assemblies – The DPUs for the normal telescopes x 32!! – Scientific support and algorithms • Exoplanet detection (CAB) • Asteroseismology (CAB - A. Moya + IAA – J.C Suárez)
PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 35 PLATO SEA 2010 17-09-2010 J. Miguel Mas-Hesse 36