Pr

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?????? PLATO in the context of the extrasolar
planet research Giusi Micela (INAF-OAPa)
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Outline

• Cosmic Vision context
• Relevance of transits for extrasolar planet
  search
• PLATO contribution
• Beyond PLATO

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Cosmic Vision

• On 18 October 2007, ESA selected for an
  Assessment Study 6 M-class and 3 L-class
  candidate mission concepts resulting from the
  first Call for Mission for the Cosmic Vision
  plan.
• These mission concepts are competing for launch
  opportunities in 2017/2018.
• down-selection for definition phase for M-class
  missions in fall 2009
• final selection for flight of M-class mission in
  2011

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M-class missions

• Solar mission
• Space Plasmas
• NEO
• Dark energy
• (Dune Space)
• Infrared (Japan)
• Extrasolar planets

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Known exoplanets

• 316 planets in 270 systems, Oct 1995 - Feb 2009
  from RV searches. 33 multiple systems.
• 57 Transiting planets
• 7 from microlensing surveys.
• a few others

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ESP population synthesis
Left panel Core accretionmigration simulations
by Ida Lin (2004), showing gas giants, ice
giants, rocky planets. around solar-like
stars Right panel Radial-velocity discovered
planets.
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Planetary search methods domains

• Transits due to Earth-like planets can be
  detected with accurate (10-4) photometric
  searches. ? only from space

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• New planets are continuously discovered.
• The number of new discovered transits is quickly
  increasing
• (2/3 in the last two years)

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Transits

• For an edge-on orbit, transit duration is
• Dt (PR) / (pa)
• Pperiod, asemi-major axis of orbit
• Probability of transit
• Ptransit R / a
• For Earth (P1yr, a1AU), Ptransit0.5
• But for close, hot Jupiters, Ptransit10
• Of course, to detect Earths at 1 AU we need to
  monitor the star for up to 1 year

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Transits

• Advantages
• Easy. Can be done with small, cheap telescopes
• Possible to detect low mass planets, including
  Earths, especially from space
• Disadvantages
• Probability of seeing a transit is low
• Need to observe many stars simultaneously
• Easy to confuse with starspots, binary/triple
  systems
• Needs radial velocity measurements for
  confirmation, masses

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Transits

• Radial velocity Transits
• Porb, dist, mass, radius, density, inclination
• Transits from ground ? Jupiters
• Transits from space ? Earths

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• Radial velocity follow up are needed to determine
  the properties of transit discovered planets
• Critical point. Transits from space may now
  detect earth-size planets ? bottle neck due to
  limiting vrad measurement capabilities. We need
  to measure cm/sec
• Very stable spectroscopes, new
  generation telescopes

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• We need also to know very well the host
  properties
• ? Rpl f(R)
• ? Mpl f(M)
• age age
• Bright stars!!

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Observational properties

• Mass distribution for vrad-discovered planet
  (upper) and transiting planets (lower)

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Observational properties

• Orbital distance distribution for
  vrad-discovered planet (upper) and transiting
  planets (lower)

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The first space transit mission CoRoT

• French mission with ESA contribution
• Launch Dec. 2006 , extension of 3 years more
• Extrasolar planets and asteroseismology
• Six planets already discovered
• Many candidates
• Very long follow up phase

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Convection Rotation and planetary Transits - CoRoT
Wide field telescope (27cm aperture) with 4 deg
field. Most stars from 11-15Mag.

• 6 planets
• EXO-2 orbiting a young active star
• EXO-3 high mass, compact object
• EXO-7 rocky (2xR(Earth)) with P0.85d

AA Cover
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Convection Rotation and planetary Transits - CoRoT
Wide field
Planetary transits
AA Cover
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?????? PLATO PLAnetary Transits Oscillations of
stars
Next generation mission for ultra-high precision
stellar photometry beyond CoRoT Kepler
Search for and characterisation of exoplanets
asteroseismology
http//www.lesia.obspm.fr/cosmicvision/plato http
//www.oact.inaf.it/plato/PPLC/Home.html
Class-M mission under assessment study at ESA in
the framework of  Cosmic Vision  programme
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The science objectives of PLATO PLAnetary
Transits Oscillations of stars
main objective evolution of exoplanetary
systems ( planets host stars)

• - the evolution of planets and that of their host
  stars are intimately linked
• - a complete precise characterisation of host
  stars is necessary to
• measure exoplanet properties mass, radius, age
• compare planetary systems at various stages of
  evolution
• correlation of planet evolution with that of
  their host stars

comparative exoplanetology
Three kinds of observables 1. detection
characterisation of planetary transits 2. seismic
analysis of exoplanet host stars 3. complementary
ground based follow-up (spectroscopy)
seismic analysis - R, M, age - interior
transit detection - Porb, Rp/R, R/a
spectrum, RV, photometry, imaging, - exoplanet
confirmation - chemical composition of host
stars - and of exoplanet atmospheres
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Scientific Requirements
main science objectives - detection and study of
Earth-analog systems - exoplanets around the
brightest stars, all sizes, all orbital periods -
full characterisation of planet host stars, via
seismic analysis
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Scientific Requirements
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Main Instrument Requirements
- very wide field gt 550 deg2 (CoRoT 4 deg2
Kepler 100 deg2) - 2 successive fields (2 x 3y)
step stare phase (1y e.g. 4 fields x 3
months) - large collecting area - very low
instrumental noise, in particular satellite
jitter 0.2 arcsec
requirements for ground- and space-based
follow-up - high precision radial velocity
measurements false-alarm elimination, masses -
high resolution spectroscopy chemical
composition - differential spectroscopy
exoplanet atmosphere composition
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The PLATO study organization
ESA study scientist, study manager, payload
manager M. Fridlund R. Lindberg
D. Lumb
ESA PSST
PLATO
Consortium Council
2 industrial contractors Payload SVM
PPLC PLATO Payload Consortium
PSC PLATO Science Consortium
PI D. Pollacco Co-Pis G. Piotto H.
Rauer S. Udry
PI C. Catala Co-Pi M. Deleuil
study of payload system telescopes/optics
Focal Plane onboard data processing ground
data centre
science case scientific preparation field
characterisation and choice follow-up observations
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The PPLC Payload concept
- fully dioptric design - 11cm pupil, 28x28
field - FPA 4 CCDs 35842, 18? - 40 normal
telescopes full frame CCDs cadence
25s 8 mV 14 - 2  fast  telescopes frame
transfer CCDs cadence 2.5s 4 mV 8 -
overlapping line-of-sight concept - 2 long
pointings (3 yrs) - 1 yr step stare
continuous observation, field rotation every 3
months
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Performance of PPLC baseline design
magnitude for noise 27 ppm in 1 hr
highest priority requirement gt 20,000 cool
dwarfs with noise lt 27 ppm in 1 hr
P1 sample
26500
P2 sample
61000
P5 sample
303000
performance of initial industrial design, now
being improved
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Performance of PPLC baseline design
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Performances
planets down to 1 Rearth around late-type stars
with mV12-13 (gt300,000 stars incl. 60,000 with
potential seismic analysis )
planets down to 0.6 Rearth around G-type stars
with mV9.6-11.1 with seismic analysis (26,500
stars)
P5
P2
P1
transit depth detected at 3 ? if duration 10h
telluric planets around stars up to A-type with
mV9.6-11.1
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PLATO outcome (1)

• PLATO will search planets orbiting bright stars.
  
• It will therefore possible to follow up the
  exo-planetary system with ground based and space
  telescopes (e.g., ELT, JWST, etc. ) to obtain a
  complete characterization of the planet, its
  atmosphere, and the whole planetary system
• PLATO is the only instrument with this
  capability!

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PLATO outcome (2)

• PLATO will detect Earth-like planets
• Small size planets orbiting solar-type
  stars with about 1 year period
• The exo-planets discovered by PLATO can be
  fully characterized
• The same data that PLATO acquires for the
  planet search, are
• used to derive the internal structure of
  the hosting stars (by asteroseismology). This is
  mandatory to
• Precisely measure properties of exoplanets mass,
  radius, age
• Comparatively study planetary systems of
  different age
• Correlate the planet and hosting star evolution.

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PLATO outcome (3)
PLATO will provide a complete and unbiased
database to understand the evolution of stars
and their planets

• PLATO will bring us
• complete characterization of large number of
  exoplanets
• (size, mass, age,density)
• - improvement of exoplanet statistics
• - correlation planetary versus stellar evolution
• - decisive progress in stellar and planetary
  evolution modelling

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• Date March 6 Mission Kepler Launch Vehicle
  United Launch Alliance Delta II Launch Site
  Cape Canaveral Air Force Station - Launch Complex
  17 - Pad 17-B Launch Time 104957 p.m. EST
  Description The Kepler Mission, a NASA
  Discovery mission, is specifically designed to
  survey our region of the Milky Way galaxy to
  detect and characterize hundreds of Earth-size
  and smaller planets in or near the habitable
  zone.

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Time will tell but35 hot Jupiters bright enough
for RV confirmation (14th mag) - HARPS-N
WHT.Superearths? Yes - probably
manyTerrestrial planets? ProbablyEarth
analogs??but difficult to be confirmed through
follow up\
Kepler Results (!)
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Next stepsAfter characterizing the star-planet
systems

• Substantial progress in theories of planet
  formation for giant and terrestrial planets
• Atmospheric properties (giants soon, earths ?)
  Albedo, clouds, dynamics, temperature,
  composition
• Habitability conditions (environment)
• Biosignatures, identification and observations

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Next steps

• Technical issues
• The best technology ? interferometry or
  coronography from space
• Ids of the best target samples nearby solar type
  very quiet stars with planet(s) in habitable zone
  ? PLATO could furnish some

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Next steps

• Significant effort of the community to prepare a
  roadmap for extrasolar planetary science
• ESA EPR-AT (Exo-Planet Roadmap Advisory Team)
  will deliver a document next year (spring)
  meeting open to the community Jan-Feb 2010
  (http//sci.esa.int/science-e/www/object/index.cfm
  ?fobjectid42830)
• BLUE DOTS Initiative of the community to prepare
  a roadmap for detection and characterization of
  habitable exoplanets. Conference in Barcelona
  (Sept. 2009)
• (http//www.blue-dots.net)

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Just to conclude

• Extrasolar planet science is growing very quickly
• A fluorishing of new projects and instruments
  from ground and from the space
• with PLATO we will know, on solid statistical
  bases, which kind of planetary systems exist and
  their properties
• PLATO is part of a roadmap that will bring us in
  some decades (?) to biosignature detection in
  extrasolar planet atmospheres

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Performances