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COROT,COnvection

ROtation and planetary Transits

Ennio PORETTIEnnio PORETTIINAF – Osservatorio Astronomico di BreraINAF – Osservatorio Astronomico di Brera

COROT mission: scientific profileand preparatory ground-based observations

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Woman with a pearl Louvre

Jean Baptiste Camille COROT (1795-1875)

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The Bridge at Nantes Louvre

Jean Baptiste Camille COROT (1795-1875)

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OUTLINESOUTLINES

THE MISSION

The consortium, the persons, the satellite The orbital plane, the observing modes The scientific profiles

THE PREPARATORY WORK FOR ASTEROSEISMOLOGY

Target selection in the Center and Anticenter directions Target characterisation Future activities

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7 countries or organizations are officially collaborating and supporting the mission

AustriaElectronic parts

SpainMission Center

GermanyOn-fly software

BelgiumCase and Baffle

BrasilSecondary antenna

ESAOptics

SSDProcessors Instrument

Ground segment

International PartnersInternational Partners

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Launched on December 27, 2006New SOYUZ rocket from Baïkonour

A. Baglin Principal Investigator

Th. Lam-Trong Project Manager

M. Auvergne Project Scientist

L. Boisnard Mission Engineer

Documentation :

http://corot-mission.cnes.fr

http://www.obspm.fr/planets

http://www.astrsp-mrs/projets/corot

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General characteristics

Aperture : 4.20 m x 9.60 m

PROTEUS platformDeveloped by CNES and Alcatel Space for low orbits.

First flight in 2001 : JASON oceanographic satellite

5 missions are scheduled

Mass : 600 kg (launch configuration)

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Telescope (COROTEL) entrance pupil 270 mm 2 parabolic mirrors cylindric external baffle cylindric internal baffle shutter

Instrument (COROTCAM) 6 lents Detectors: 4 CCD 2048 x 2048 Radiation shielded 2 CCD seismology, 2 CCD exoplanets Field of view : 3.05° x 2.70°

Optical design

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OUTLINESOUTLINES

THE MISSION

The consortium, the persons, the satellite The orbital plane, the observing modes The scientific profiles

THE PREPARATORY WORK FOR ASTEROSEISMOLOGY

Target selection in the Center and Anticenter directions Target characterisation Future activities

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Winter : line of sight at 6 h 50

Sun at 90o from COROT: rotation of the satellite

Summer: line of sight at 18 h 50

Orbital parameters

• a = 7274 km (altitude =896 km)

• e = 1.27.10-3

• i = 90o

• Torb = 6174 sec (1 h 43 min)

Orbit

Polar orbite, low altitudeIt allows to maintain the same direction of observation for 6 months

without be disturbed by sun light or undergo Earth eclipses

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0°

30°

60°

90°

120°

150°

180°

210°

240°

270°

300°

330°

0h2h4h6h8h10h12h14h16h18h20h22h

SummerZone of observationcentered at 18h50

WinterZone of observationcentered at 6h50

Galaxy

The two COROT eyes

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0E2

CCD A1 CCD E1

CCD E2CCD A2

0E1

0A1

0A2

3.05°

2.70°

AsteroseismologyBright stars 5.5 < V < 9.510 in each field

Exoplanetary searchFaint stars 11.0 < V < 16.512 000 in each field

Mission life expected : 2.5 y5 long runs (150 d each)10 short runs (20 - 30 d)

V = 6 --> ~2.5 104 photons cm-2 s –1

outside atmosphere , T ~ 6000°Kmv = 16 --> ~2.5 photons cm-2 s -1

The observing modesThe observing modes

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Stellar photometry with a very high accuracy on a long time baseline

Seismology : 6 micromag, V=6.0 in 5 days Planetary transits : 0.1 mmag on a V=15.5 star

Two scientific goals, simultaneously performed in two adjacent sky regions

The communalitiesThe communalities

Asteroseismology Exoplanet search

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OUTLINESOUTLINES

THE MISSION

The consortium, the persons, the satellite The orbital plane, the observing modes The scientific profiles

THE PREPARATORY WORK FOR ASTEROSEISMOLOGY

Target selection in the Center and Anticenter directions Target characterisation Future activities

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The SunParameters Helium content and core radius, depth of convection zones, internal rotation profile…

Asteroseismology

Sounding to stellar interiors and physical processes Frequencies of the oscillation modes (both pression and gravity) on a a wide

range of values

photometric precision of 6 ppm (white noise) on a V=6 star in 5 days of

continuous monitoring

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Search for Earth-like planets

detection by means of transits across the disk of parent star

photometric precision around 10-4 down to V=15.5

Detection criterium : repetitivity (150 d runs)

colour information (3 ‘filters’ available) to disentangle between stellar

activity and transits

Terre : 10-4 , Jupiter : 10-2

Exoplanet SearchExoplanet Search

Planets searched by COROT (transits)

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Exoplanetary CCDsAcquisition

5 000 x 2 windows in 3 colours

40% in red, 30% in blue for a K0 star

1 000 x 2 windows monocromatic

20 imagettes (10x15 pixels)

Aperture photometry Exposure time 16 x 32 s

oversampling on request

ADDITIONAL PROGRAMS

Exoplanet searchExoplanet search

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0

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(Butler et al. 2000, ApJ 545, 504)

Asteroseismic target.Known to host at least one planet.

Visit the site http://media4.obspm.fr/pianeti-extrasolari/

HD 52265

20e Festival d'Astronomie de Haute Maurienne

20 E. Michel COROT

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ADDITIONALPROGRAMS

(seismology in the exoplanetary channel)

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THE FUTURE OF THE EXOPLANETARY SEARCH

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THE PHOTOMETRIC AND SPECTROSCOPIC MONITORING OF THE COROT TARGETS

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OUTLINESOUTLINES

THE MISSION

The consortium, the persons, the satellite The orbital plane, the observing modes The scientific profiles

THE PREPARATORY WORK FOR ASTEROSEISMOLOGY

Target selection in the Center and Anticenter directions Target characterisation Future activities

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SUMMARY OF THE PREPARATORY WORK

Ground-based observations: high-resolution spectroscopy usingFEROS at ESO and SARG at TNG and detailed reductions Solano et al., 2003 (GAUDI ARCHIVE)

Identification of new primary targets in the Center direction Poretti et al., 2003

Identification of secondary targets in the AntiCenter direction Poretti et al., 2005

Preliminary asteroseismic characterisation of primary targets (in progress)

Target selection in the instability strip is based on the matching betweentheory and observation. Large experience from ground-based campaigns

SPECTROSCOPIC GROUND-BASED CHARACTERISATION OF COROT TARGET Large Programmes at ESO and OHP, complementary runs in other sites

GALACTIC CENTER DIRECTIONThe summer 2002 challenge : find new variables in the Lower Instability Strip for COROT

Too few primary targets. Necessity to enlarge the primary targets list. Which stars are actually variable ones ?

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Challenge won !!! Observations performed mainly at OSN and SPM

New targets proposed to the COROT Scientific Committee (December 2002, Corot Week 3)

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Short list of candidate primary targets in the Center direction

Solar like star HD 177552

Gamma Dor star HD 171834

Delta Sct stars HD 181555 * HD 170699 **

Beta Cephei stars HD 170580 ** HD 180642 *

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ANTICENTER DIRECTION uvby (OSN and SPM) and CCD (STARE) photometry down to V=10.0 around primary targets only

RED SQUARES : new DSCT stars

OTHER SYMBOLS : constant stars

SMALL DOTS : stars far from primary targets

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OUTLINESOUTLINES

THE MISSION

The consortium, the persons, the satellite The orbital plane, the observing modes The scientific profiles

THE PREPARATORY WORK FOR ASTEROSEISMOLOGY

Target selection in the Center and Anticenter directions Target characterisation Future activities

THE TARGET CHARACTERISATION: photometry

Sierra Nevada Summer 2004 P. Amado and S. MartinS. Pedro Martir Summer 2004 E. PorettiMt. Piszekesteto September 2004 M. Paparò and coll.

Sierra Nevada Winter 2004-05 P. Amado and S. Martin S. Pedro Martir Winter 2004-05 M. Alvarez and E. PorettiAPT Winter 2004-05 W.W. Weiss

Mercator Summer 2005 C. Aerts and coll.Mt. Piszkesteto Summer 2005 M. Paparò and coll.Sierra Nevada Summer 2005 S. MartinS. Pedro Martir Summer 2005 M. Alvarez

S. Pedro Martir Winter 2005-06 E. Poretti, M. Alvarez and STEPHI Sierra Nevada Winter 2005-06 S. Martin and E. RodriguezMt. Piszekesteto Winter 2005-06 M. Paparò and coll.

S. Pedro Martir November 2006 E. Poretti and K. UytterhoevenSierra Nevada Winter 2006-07 E. Rodriguez and S. Martin

Positions of the DSCT+GDOR targets in the CMD

1 HD 44195 GDOR+DSCT

2 HD 181147 DSCT

3 HD 50870 DSCT

4 HD 170782 DSCT

5 HD 170699 DSCT

6 HD 44283 DSCT

7 HD 172189 EA+SB2+DSCT

8 HD 181555 DSCT (revised)

9 HD 49434 GDOR

10 HD 171834 GDOR

11 HD 180642 BCEP12 HD 170580 BCEP

(Poretti et al. 2005, AJ 129, 2461)

Metallicities, masses and luminosities of the DSCT+GDOR targets

1 HD 44195 GDOR+DSCT

2 HD 181147 DSCT

3 HD 50870 DSCT

4 HD 170782 DSCT

5 HD 170699 DSCT

6 HD 44283 DSCT

7 HD 172189 EA+SB2+DSCT

8 HD 181555 DSCT

9 HD 49434 GDOR

10 HD 171834 GDOR

Evolutionary tracks calculatedby Y. Lebreton and J.C. Suarez.

Temperatures and Magnitudescalculated by P. Amado from Stromgren photometry.

THE LOWER PART OF THE INSTABILITY STRIP : the DSCT bookmarks Stars in different physical conditions

ZAMS :

1 HD 181555 7.98 170 primary target 2 HD 44195 7.57 58 HD43587

UNEVOLVED :

3 HD 181147 8.74 --- HD181555 4 HD 50870 8.86 17 HD52265 5 HD 170782 7.81 197 HD170580 6 HD 170699 6.95 >200 HD170580

ZIGZAGS (TAMS)

7 HD 44283 9.29 19 HD43587 8 HD 172189 8.85 EA HD171834

(Poretti, 2000) (Garrido and Poretti 2004)

The investigations of Delta Sct stars are of course very preliminary. The frequency detection depend on the S/N.

Target selection in the instability strip is based on the matching between theory and observation. Large

experience from ground-based campaigns

20e Festival d'Astronomie de Haute Maurienne

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HD 44195, new DSCT star in the HD 43587 field

Power spectrum showingvariability at low frequencies(f<5 c/d; GDOR regime ?)and at high frequencies(f>20 c/d; DSCT regime).

Unevolved object.

Slow rotator : v sin i = 58 km/s

PERFECT Delta Sct FOUNDUnevolved : no dense frequency spectrum, no mixed modes

Slow rotator : a relief for theoreticians, though progresses have been made in the treatment of fast rotators.

NOVEMBER 2003 (8 nights) JANUARY 2005 (4 nights)

HD 44195, the hybrid GDOR + DSCT star v sin i = 58 km/s, in the field of HD 43587, f1=20.48 c/d

NOVEMBER 2005 (6 nights)

The DSCT variability seems to be monoperiodic,The GDOR variability seems to be multiperiodic

20e Festival d'Astronomie de Haute Maurienne

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HD 44195

Hybrid variable, just one pulsation athigh frequency.

Power spectra from Stromgren photometry.Light curves from Mt Piszekesteto Observatory.

HD 44283, multiperiodic DSCT variable,small v sin i (19 km/s), evolved (?)

15.00 c/d, predominant mode (ampl. 0.014 mag in v)

Second term, f=15.96 c/d,

(ampl. 0.005 mag in v)

Asteroseismic peaksaround 10 and 20 c/d,(ampl. < 0.003 mag in v)

HD 49434, confirmation of the light variability

High precision photometry(s.d. better than 0.002 mag)on four consecutive nights.

Peak-to-peak amplitudes0.022 mag in violet0.019 mag in blue0.016 mag in yellow

Multiperiodicity probable.Observations recently obtained(OSN, SPM and Mt. Piszekesteto)will be decisive to detectperiodicities.

Additional APT timeseries available.

HD 50870, a DSCT star in the field of HD 52265

f1=17.15 c/df2=14.00 c/d……….

Slow rotator,Veq sin i = 17 km/sPredominant mode

STEPHI campaignin November 2005

Field of HD 171834

HD 172189 : DSCT and eclipsing binary in the open cluster IC 4756

HD 172189, orbital period has been detected: 5.702 d.Eccentric orbit with only one minimum.DSCT pulsation: frequencies in the 18-20 c/d interval.(Martin et al., 2005, A&A 440, 711)

The RV curvehas been the goal of successfulspectroscopicobservations inpast summer(OHP, SLN, ESO).

Target of a STEPHI campaignin 2004.

HD 172189 not only an Eclipsing Binary, but probably also a Spectroscopic Binary (SB2)

FEROSspectrum,June 2004

HD 181555 – Candidate primary target

Fast rotator : Vsin i > 200 Km/s

Observed both at OSN and SPM. Evidentmultiperiodicity: set of frequencies in the 8-11 c/d interval.

HD 180642, Beta Cep variable

Monitored at SPM and OSN in Stromgren photometry,with Mercator telescope in the Geneva system and and with M. Piszkesteto telescope in V filter

Main pulsational frequency term identified as the Fundamental radial mode; additional termsprobable (Aerts et al., in preparation)

Reminiscent of the case of BW Vul (Sterken and coll.)

HD 180642, Mercator andMt. Piszkesteto light curvesin V light

BW Vul

HD 44195 hybrid HD 43587 f=20.5 c/d f< 5c/d 7.56 F0 58 km/sHD 50870 DSCT HD 52265 f=17.5 13-15 8.88 F0 17 km/sHD 44283 DSCT HD 43587 f=15.0 10-25 9.29 F5 19 km/s

HD 181147 DSCT HD 181555 f=15.4 14-17.5 c/d 8.74 A5 98 km/sHD 170782 DSCT HD 170580 13-25 c/d 7.81 A2 197 km/sHD 170699 DSCT HD 170580 10-15 c/d 6.95 A3 >200 km/sHD 172189 DSCT HD 171834 17-19 c/d EA +SB2 8.85 A2 48 and 75HD 181555 DSCT primary target 8-18 c/d 7.98 A5 170 km/s

HD 49434 GDOR photometric variability CONFIRMED 5.75 F1 90 km/sHD 171834 GDOR no photometric variability 5.43 F5 72 km/s

HD 180642 BCEP HD 181555 f=5.49 c/d, standstill 8.29 B1 37 km/sHD 170580 BCEP no photometric variability, multiple system 6.68 B2V

Target Type Field Frequencies V Sp V sin i

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OUTLINESOUTLINES

THE MISSION

The consortium, the persons, the satellite The orbital plane, the observing modes The scientific profiles

THE PREPARATORY WORK FOR ASTEROSEISMOLOGY

Target selection in the Center and Anticenter directions Target characterisation Future activities

Future activities supporting COROT observations

Multicolour photometry : OSN, SPM, Mercator, Hungary, APT,…

detection of predominant modes and frequency ranges low degree identification by phase shifts & amplitude ratios

High resolution spectroscopy : OHP, SLN

radial velocity curves characterization of GDOR variables Line Profile Variations for BCEP and DSCT stars

The spectroscopic counterpart of the COROT observations

FG Vir (Zima et al. 2006)

TARGETS FOR COORDINATED GROUND-SPACE OBSERVATIONS Preliminary list (ESO and OHP targets)

P78 IR1 P79 LRc1 P80 LRa1 P81 LRc2

HD 50844 DSCT 9.1 HD 180642 BCEP 8.3 HD 49434 GDOR 5.8 1° field HD 181555 DSCT 8.0 HD 50209 Be 8.4 HD 171834 GDOR 5.4 HD 181231 Be 8.6 HD 49330 Be 8.9 HD 172189 DSCT 8.8 2° field SR1 (?) HD 170580 BCEP 6.7 HD 183324 LBOO 5.8 HD 170699 DSCT 6.9 HD 183656 Be 6.1 HD 170782 DSCT 7.8 HD 171219 Be 7.6 SR2 (?)

HD 175337 bona-fideGDOR 7.4 HD 174966 DSCT 7.7 HD 174936 DSCT 8.6

A careful planning of the observations (which star at which site) is mandatory. Bright targets can more conveniently observed at Calar Alto.

CONCLUSIONS

In the past decades we performed a lot of observational efforts to make progress in asteroseismology.

All the know-how is now at the service of the COROT mission.

In turn, CoRoT is offering us the possibility to improve rapidly our knowledge of stellar interiors.

We have the possibility to consign a more mature science to young researchers.

We are happy to be in the play, though it is not a simple one.

But it’s challenging, and we like that.