* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Exoplanet Working Group
Fermi paradox wikipedia , lookup
Cygnus (constellation) wikipedia , lookup
Geocentric model wikipedia , lookup
Copernican heliocentrism wikipedia , lookup
International Ultraviolet Explorer wikipedia , lookup
Observational astronomy wikipedia , lookup
Corvus (constellation) wikipedia , lookup
History of astronomy wikipedia , lookup
Space Interferometry Mission wikipedia , lookup
Circumstellar habitable zone wikipedia , lookup
Aquarius (constellation) wikipedia , lookup
Planets beyond Neptune wikipedia , lookup
Rare Earth hypothesis wikipedia , lookup
Solar System wikipedia , lookup
Kepler (spacecraft) wikipedia , lookup
Astrobiology wikipedia , lookup
Satellite system (astronomy) wikipedia , lookup
Astronomical naming conventions wikipedia , lookup
Late Heavy Bombardment wikipedia , lookup
Formation and evolution of the Solar System wikipedia , lookup
Planets in astrology wikipedia , lookup
Nebular hypothesis wikipedia , lookup
Directed panspermia wikipedia , lookup
Extraterrestrial life wikipedia , lookup
Definition of planet wikipedia , lookup
IAU definition of planet wikipedia , lookup
Timeline of astronomy wikipedia , lookup
Ancient Greek astronomy wikipedia , lookup
History of Solar System formation and evolution hypotheses wikipedia , lookup
Exoplanetology wikipedia , lookup
Exoplanet Working Groups CoRoT Brazil Workshop Natal 2004 : oct 29th – nov 2th CoRoT-Brazil Pierre BARGE • Summary on exoplanet discoveries • Challenge on the terrestrial planets and the place of CoRoT • Present organizing of the Exo WG CoRoT-Brazil Exoplanet search main results (RV from 1995 to 2004) • 7% of dwarf stars around Sun host giant planets (EGP) • Stars with planets have spectral types from F to M • Statistical studies become possible ( 130 EGPs) • EGP are preferentially found around metal-rich stars • Orbital periods range from ~1.5 days to some years • Large eccentricities are common ( 0 < e < 0.927) • Planet masses range from 14M to 10MJup • Mass distribution peaks toward small planets • Density of the planets is determined in some cases • 10 multi-planets discovered (some commensurabilities) • Some planets are found in binary star systems CoRoT-Brazil Mass/period segregations Min-mass/period R: single dwarf stars (binaries and evolved * removed) ● heavy planets ( >2 ) ○ intermediate (0.75 > ; <2 ) ∆ light planets (< 0.75 ) Orbital period distribution -red: heavy -grey: light (<0.75) CoRoT-Brazil (After Udry et al. 2003) Parent star metallicity (After Santos et al. 2003) Signature of the core instability scenario ? Result of engulfed migrating planets ? CoRoT-Brazil Summary on Giant Planets – Commonly form around stars (single or binaries) – Have masses in a wide range (0.6 < m < 10 mJup ) – Can be found in the inner part of the system – Can have orbits with very large eccentricities Strong differences with our Solar System We still do not know how do they form ! • Core instability in a layered nebula • Gravitational instability in a gas nebula CoRoT-Brazil About terrestrial planets – Well defined problem adressed in terms of kinetic equations and numerical simulation, both. – The standard formation scenario is accretion by planetesimal accumulation (Safronov 1969) Planetesimals moon sized bodies (105 yrs) or bigger planetary embryos Good agreement and common consensus Final stage: Embryos T. Planets Depends on the presence and location of G. planets ! CoRoT-Brazil Close-in terrestrials: a very “hot” question • Planets with mass similar to that of Uranus were recently discovered by RV method (14 – 20 m) • Are they Uranus like (migrated/evaporated) or big terrestrial ? Their density (radius) is required CoRoT will permit: • • • • To answer the above question To discover other such planets To test a number of emerging models To start statistics of terrestrial planets … CoRoT-Brazil Exoplanets: Two Working Groups E.W.G. E.C.O.W.G. (Exoplanet Working Group) (Exo. Complementary Obs. WG) Coordination of sci. activities Coordination of obs. Effort • Transit detection • Stellar “noise” • Works on specific topics (planetary formation, physics of Gas Giants, atmospheres and wind, magnetosphere, tidal effect, dynamical stability, planets in binaries, …) CoRoT-Brazil • • • • • Preparatory observations Follow-up Complementary observations …… Scientific data base (Exodat) Cf. Magali’s talk E.W.G. Objectives and Strategy • Objectives – To optimize the impact of CoRoT data on exoplanetary science – To organize the scientific activity in various working teams – To make people work together – To stimulate exchanges between seismo and exo communities (stellar activity as a noise, metallicities and spectral types, ….) The difficulty lies in beginning to work with no data …! • Strategy Brain storming during Planet workshops Specific works decided during Exo sessions at CWs CoRoT-Brazil The Planet Workshops • PW1: “Planetary formation: toward a new scenario” (june 2-3 2003): • PW2: “Planetary transit detection: stellar noise and false alarms” (dec 8-9 2003): • PW3: “Close-in exoplanets: the star-planet connection” (may 13-14 2003): • PW4: “Automatic Spectral Classification for large data sets” (reported) • PW5: … to be defined at the next CoRoT Week in Granada CoRoT-Brazil Some specific works • Simulation of the stellar activity Two different approaches: – Rotational modulation by dark spots and active regions calibrated on Virgo-Soho data – Microvariability deduced from a spectral analysis of Sun variations • Simulation of light-curves and transits • Blind test of the detection algorithms using simulated light-curves CoRoT-Brazil Points raised at PW2 on transit detection • How to compare and merge the capabilities of the various methods ? • How to build up again a detected transit ? (least square fitting, Bayesian,….) • Estimate others false alarms possibilities • How to face stellar noise ? Appropriate filtering ….. Use of colors (CoRoT, Eddington? ) CoRoT-Brazil Main conclusions of PW2 • Eclipsing binaries – probably one of the main sources of confusion – also good targets for planet search ! • Radial velocity follow up – Not a method to remove false alarms – Can remove confusing situations – Adds important information (mass) • Testing detection algos. would require working on the same light-curves and blindly Proposal: Free exchanges of light-curves between the various teams CoRoT-Brazil Detecting transit blindly (1st test – CW5) This test involved various teams in our groups (initiated during CW5): • To produce simulated light-curves which account for: – – – – Instrumental noises Noises from the stellar variability Planetary and stellar signals (possible ambiguities) A sample of 1000 LCs were produced (secret: 1 person) • To look for possible transits using different detection algorithms – Five different teams were involved (open to all CoIs) – To work on a common set of LCs for relevant comparisons CoRoT-Brazil Conclusions of 1st blind test • Very different detection methods tested • False detections seem specific to the algo. used • Stellar micro-variability is not the main limitations • The method used to detrend the signal is almost as important as the detection algorithm itself • In some cases detrending can produce artefacts • Background eclipsing binaries are source of confusion • Characterization of the transits requires other analysis of the signal • CoRoT detectivity limitation: (1.1 R 3days) on M0 dwarf stars Results are to be published and LCs will be available on request CoRoT-Brazil Conclusions of PW3 PW3 was devoted to the Close-in Exosolar planets and the relations they have with the host star. • A lot of interesting points were addressed: – – – – Existence of extremely hot giant planets (3 confirmed) Evaporation rate of hot jupiter planets is strong Origin of the overmetallicity of stars (primordial or not?) How such planet form ? Migration ? – Relations with the host star (tidal effect, radiative and magnetic interactions) – Possible existence Hot Uranus, big rocky planets (primordial or evaporated remnants), big liquid planets, …. Many questions CoRoT will help to solve soon ! CoRoT-Brazil Next work within EWG To detect transit blindly using 3-color lcs • This test will involve the detection teams of EWG • LCs will be simulated using the instrument-model (M.Auvergne) to account for realistic noises • Transits and ambiguities will be included as in the first blind test • This will be a good opportunity to test how color information can improve CoRoT detection capabilities CoRoT-Brazil