Schedule of CoRoT and Kepler CoRoT Launch: First image: First scientific observations: First planet detected 87 days after begin of observations KEPLER Launch: First image: Start of scientific operations: days after begin of scientific observations will be August 8th.

Searching for extrasolar planets with CoRoT (Convection, Rotation et Transites planétaires) Du cœur des étoiles aux planètes habitables

CoRoT Mission Scientific Objective  1.) Detecting oscillations of solar like stars  2.) Detecting transiting gaseous planets  3.) Derive radius, mass, density of gaseous planets to obtain mass-radius relation  4.) Determine frequency of short-period massive planets.  5.) Mission has fair chance to detect even rocky planets

The satellite Mass: 605 kg Dimensions: 4.2m wide by 9m high

Optical design: telescope of 27cm aperture 1.2 m focal length 2.3 arsec per pixel FOV 2.8x1.4 degrees for the Exo-field

The baffle reduces stray-light from earth by factor , however because of the zodical light, the background flux still is 15 phot/pix/s.

4 CCDs (2048x2048 pixel): 2 for Exo-field, 2 for stellar oscillations T=-40C, telemetry 1.5 Gbyte/day

Exo field: little spectra (R=4, 100nm/pix) (40% in red, 30% in green, 30% in blue)

Advantages of space observations  Photometric accuracy 10 to 100 times better than with ground based telescopes. While ground based observations reach a level of better than 1%, not all nights are perfect. In many nights this means that the photometric accuracy for all faint stars is bad. Because all stars are effected at the time, this creates so- called “red-noise”, which has proven to be the big problem of ground based photometry.  Continuous light-curves without gaps allow to distinguish spots from transits.  CoRoT monitors fields for 150 or 20 days. (long/short runs).  The sampling is 8 minutes for all stars, if it is discovered that an object has transit, the frequency is increased to 30 seconds. That means, each LC has between 3600 and 3x points. CoRoT database is by far the largest photometric data-base ever obtained.  Three colour photometry allows to exclude eclipsing binaries within the photometric mask.

Noise sources  Background noise (Zodiacal light)  Readout noise  Jitter noise  “ Breathing noise ” due to tiny changes of the temperature of the telescope structure  Photometric accuracy to a few times10 -4.

Launch :

Orbital parameters  Semi major axis km  Orbital inclination 90 degrees  Eccentricity

The eyes of CoRoT

Observations in pace versus ground: Observations in space allow continuous monitoring. That means we can detect transit of planets with much longer orbital period. Here is a comparison with SuperWASP, which is located at the island of La Palma.

The other big advantage of observations in space is that spots and transits can easily be distinguished, and we get the rotation rate of the star for free!

Stars that are being observed In order to get statistically meaningful results, we have to determine the spectral types (mass) of all the stars that we are looking at. A first analysis of the CoRoT data shows that ground based observations detect only 10% of the hot Jupiters that are in principle within reach. This is an effect of the red noise and very often also the day/night gaps of ground based observations. How do we determine the spectral types of 1000nds of stars?

Magnitude range

The superb photometric archive created by CoRoT allows us to address a large variety of different scientific questions. However, for all these projects we need to know what kind of star we are looking at. Teff, Lum. Class, log(g), [Fe/H], Av, RV, vsin(i), stellar activity level, age, etc. Teff, Lum. Class, log(g), [Fe/H], Av, RV, vsin(i), stellar activity level, age, etc. Why do we need spectroscopy? We don't want to waste time! Multi Object Spectroscopy (MOS)‏

AAOmega observations Gratings: 580V R Blue: AA; R=1300 Red: AA; R=1300

Settings: AAOmega spectrograph: 392 fibers (maximum: 367 stars + 25 sky (+ 7 feducials) Observing time per field about 45 minutes. We observed 56 fields (about spectra)

How do we determine the Spectral Type from the low- resolution spectra? –Method => we fit each observed spectrum with a suitable grid of templates, taking the amount of extinction along the line of sight into account. –What is needed? => Library of flux-calibrated and de-reddened stellar spectra covering our spectral range.

An example (observations: black, template: green)

another example......

the last one!

Comparing photometry and AAOmega - spectroscopy I: dwarfs (red: photometry, blue spectroscopy)

Comparing photometry and AAOmega - spectroscopy II: giants (red: photometry, blue spectroscopy)

CoRoT is a space telescope but we still need lots of observations with ground- based telescopes:  Spectra taken with mulit-object spectrograph: Is the star a giant or dwarf, what is the mass of the star?  Is the transit really on the star, or is there an eclipsing binary within the photometric mask (on/off photometry with high resolution).  Could the object be a triple star, with two faint companions eclipsing each other? (infrared spectra with high spectra resolution needed)  Determine the mass and the radius of the host star accurately (optical spectra with high spectral resolution and high signal to noise needed, in practise 2 to 4 hours on 8-m-telescope)  Measure the mass of the planet (can be as much as 10 nights on a 4-m-class telescope)

OGLE 56

The first one: CoRot-Exo-1b

CoRoT-Exo-1b  Star: /-0.16 Msun  Star: 1.11+/-0.05 Rsun  Star: F9V (13.6 mag)  Planet: 1.03+/-0.12 Mjup  Planet: 1.49+/-0.08 Rjup  Orbital period: days

CoRoT-Exo-1b: first planet detected in reflected light in the optical regime: nigthside: dark dayside albedo ≤20% (gas giants in solar system 41 to 52%)

A planet orbiting a young, active star

A planet of a young star:  Star: /-0.06 Msun  Star: 0.90+/-0.02 Rsun  Star: G7V (12.6 mag)  Planet: 3.31+/-0.16 Mjup  Planet: 1.47+/-0.03 Rjup  Orbital period: days

=7.1±5.0 0

S-index (sun 0.179, Eps Eri 0.496)

CoRoT-Exo-2b :log(R’ HK )= Dots, squares: Hyades Crosses: Pleiades Plus:CoRoT- Exo-2b

CoRoT-Exo-2b

An interesting aspect:  We know that the eccentricity is very small (possibly < )  This means that the orbit circularized very quickly.  This means the tidal interaction must be very strong.  The planet will spiral into the star!

NGC 2264 (distance 760pc, age 3 Myr)

A brown dwarf orbiting a normal star  Star: /-0.05 Msun  Star: /-0.02 Rsun  Star: G0V (13.3 mag)  Planet: 20.2 Mjup  Planet: Rjup  Orbital period: 4.25 days

A transiting planet with a relatively long orbital period  Star: /-0.02 Msun  Star: 1.15+/-0.02 Rsun  Star: F8V (13.7 mag)  Planet: 0.73 Mjup  Planet: 1.17+/-0.05 Rjup  Orbital period: days

Mass period-relation

KEPLER System Characteristics:  Spacebased Photometer: 0.95-m aperture  Primary mirror: 1.4 meter diameter, 85% light weighted  Detectors: 95 mega pixels (42 CCDs with 2200x1024 pixels)  Field of view 105 square degress  Bandpass: nm FWHM  Dynamic range: 9 th to 16 th magnitude stars  Fine guidance sensors: 4 CCDs located on science focal plane  Attitude stability: <9 milli-arcsec, 3 sigma over 15 minutes.

Mission Characteristics:  Continuously point at a single star field in Cygnus- Lyra region except during Ka-band downlink.  Roll the spacecraft 90 degrees about the line-of-sight every 3 months to maintain the sun on the solar arrays and the radiator pointed to deep space.  Earth - trailing orbit (heliocentric orbit with day period)  Monitor 100,000 main-sequence stars for planetsMission lifetime of 3.5 years extendible to at least 6 years

Kepler Mission Scientific Objective:  1.Determine the percentage of terrestrial and larger planets there are in or near the habitable zone of a wide variety of stars;  2.Determine the distribution of sizes and shapes of the orbits of these planets;  3.Estimate how many planets there are in multiple-star systems;  4.Determine the variety of orbit sizes and planet reflectivities, sizes, masses and densities of short-period giant planets;  5.Identify additional members of each discovered planetary system using other techniques; and  6.Determine the properties of those stars that harbor planetary systems.

Kepler: first light: March 6th 2009