COROT mission scientific profile and preparatory groundbased observations
COROT mission: scientific profile and preparatory ground-based observations COROT, COnvection ROtation and planetary Transits Ennio PORETTI INAF – Osservatorio Astronomico di Brera 1
Jean Baptiste Camille COROT (1795 -1875) Woman with a pearl Louvre 2
Jean Baptiste Camille COROT (1795 -1875) The Bridge at Nantes 3 Louvre
OUTLINES THE MISSION The consortium, the persons, the satellite l The orbital plane, the observing modes l The scientific profiles l THE PREPARATORY WORK FOR ASTEROSEISMOLOGY Target selection in the Center and Anticenter directions l Target characterisation l Future activities l 4
International Partners 7 countries or organizations are officially collaborating and supporting the mission Instrument ESA SSD Optics Processors Germany On-fly software Belgium Austria Case and Baffle Electronic parts Brasil Ground segment Secondary antenna Spain Mission Center 5
Launched on December 27, 2006 ð New SOYUZ rocket from Baïkonour A. Baglin Principal Investigator Th. Lam-Trong Project Manager M. Auvergne L. Boisnard Project Scientist Mission Engineer Documentation : http: //corot-mission. cnes. fr http: //www. obspm. fr/planets http: //www. astrsp-mrs/projets/corot 6
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General characteristics PROTEUS platform Developed by CNES and Alcatel Space for low orbits. First flight in 2001 : JASON oceanographic satellite 5 missions are scheduled Aperture : 4. 20 m x 9. 60 m Mass : 600 kg (launch configuration) 8
Optical design 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° 9
OUTLINES THE MISSION The consortium, the persons, the satellite l The orbital plane, the observing modes l The scientific profiles l THE PREPARATORY WORK FOR ASTEROSEISMOLOGY Target selection in the Center and Anticenter directions l Target characterisation l Future activities l 10
Orbit Polar orbite, low altitude It allows to maintain the same direction of observation for 6 months without be disturbed by sun light or undergo Earth eclipses Orbital parameters • a = 7274 km (altitude =896 km) • e = 1. 27. 10 -3 • i = 90 o • Torb = 6174 sec (1 h 43 min) Winter : line of sight at 6 h 50 Sun at 90 o from COROT: rotation of the satellite Summer: line of sight at 18 h 50 11
The two COROT eyes 12
The observing modes CCD A 1 CCD E 1 0 E 1 Asteroseismology Bright stars 5. 5 < V < 9. 5 10 in each field 0 A 1 Exoplanetary search Faint stars 11. 0 < V < 16. 5 CCD A 2 CCD E 2 0 E 2 12 000 in each field Mission life expected : 2. 5 y 5 long runs (150 d each) 10 short runs (20 - 30 d) 0 A 2 3. 05° V = 6 --> ~2. 5 104 photons cm-2 s – 1 outside atmosphere , T ~ 6000°K mv = 16 --> ~2. 5 photons cm-2 s -1 13 2. 70°
The communalities 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 Asteroseismology 14 Exoplanet search
OUTLINES THE MISSION The consortium, the persons, the satellite l The orbital plane, the observing modes l The scientific profiles l THE PREPARATORY WORK FOR ASTEROSEISMOLOGY Target selection in the Center and Anticenter directions l Target characterisation l Future activities l 15
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 The Sun 16 Parameters Helium content and core radius, depth of convection zones, internal rotation profile…
Exoplanet 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 Planets searched by COROT (transits) 17
Exoplanet search Exoplanetary CCDs Acquisition § 5 000 x 2 windows in 3 colours § 40% in red, 30% in blue for a K 0 star § 1 000 x 2 windows monocromatic § 20 imagettes (10 x 15 pixels) Aperture photometry § Exposure time 16 x 32 s § oversampling on request § ADDITIONAL PROGRAMS 18
HD 52265 Asteroseismic target. Known to host at least one planet. Visit the site http: //media 4. obspm. fr/pianeti-extrasolari/ (Butler et al. 2000, Ap. J 545, 504) 19
20 e Festival d'Astronomie de Haute Maurienne 20 E. Michel COROT
ADDITIONAL PROGRAMS (seismology in the exoplanetary channel) 21
THE FUTURE OF THE EXOPLANETARY SEARCH 22
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THE PHOTOMETRIC AND SPECTROSCOPIC MONITORING OF THE COROT TARGETS 20 e Festival d'Astronomie de Haute 24
OUTLINES THE MISSION The consortium, the persons, the satellite l The orbital plane, the observing modes l The scientific profiles l THE PREPARATORY WORK FOR ASTEROSEISMOLOGY Target selection in the Center and Anticenter directions l Target characterisation l Future activities l 25
SUMMARY OF THE PREPARATORY WORK Ground-based observations: high-resolution spectroscopy using FEROS 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 Anti. Center direction Poretti et al. , 2005 Preliminary asteroseismic characterisation of primary targets (in progress) SPECTROSCOPIC GROUND-BASED CHARACTERISATION OF COROT TARGET Large Programmes at ESO and OHP, complementary runs in other sites Target selection in the instability strip is based on the matching between theory and observation. Large experience from ground-based campaigns 26
GALACTIC CENTER DIRECTION The 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 ? 27
Challenge won !!! Observations performed mainly at OSN and SPM New targets proposed to the COROT Scientific Committee (December 2002, Corot Week 3) 28
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 * 29
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 30
OUTLINES THE MISSION The consortium, the persons, the satellite l The orbital plane, the observing modes l The scientific profiles l THE PREPARATORY WORK FOR ASTEROSEISMOLOGY Target selection in the Center and Anticenter directions l Target characterisation l Future activities l 31
THE TARGET CHARACTERISATION: photometry Sierra Nevada S. Pedro Martir Mt. Piszekesteto Summer 2004 September 2004 P. Amado and S. Martin E. Poretti M. Paparò and coll. Sierra Nevada S. Pedro Martir APT Winter 2004 -05 P. Amado and S. Martin Winter 2004 -05 M. Alvarez and E. Poretti Winter 2004 -05 W. W. Weiss Mercator Mt. Piszkesteto Sierra Nevada S. Pedro Martir Summer 2005 C. Aerts and coll. M. Paparò and coll. S. Martin M. Alvarez S. Pedro Martir Sierra Nevada Mt. Piszekesteto Winter 2005 -06 E. Poretti, M. Alvarez and STEPHI Winter 2005 -06 S. Martin and E. Rodriguez Winter 2005 -06 M. Paparò and coll. S. Pedro Martir 20 e Festival Sierra Nevada November 2006 Winter 2006 -07 d'Astronomie de Haute E. Poretti and K. Uytterhoeven 32 E. Rodriguez and S. Martin
Positions of the DSCT+GDOR targets in the CMD 1 2 3 4 5 6 7 8 9 10 HD 44195 GDOR+DSCT HD 181147 DSCT HD 50870 DSCT HD 170782 DSCT HD 170699 DSCT HD 44283 DSCT HD 172189 EA+SB 2+DSCT HD 181555 DSCT (revised) HD 49434 GDOR HD 171834 GDOR 11 HD 180642 BCEP 12 HD 170580 BCEP (Poretti et al. 2005, AJ 129, 2461) 20 e Festival d'Astronomie de Haute 33
Metallicities, masses and luminosities of the DSCT+GDOR targets 1 2 3 4 5 6 7 8 9 10 HD 44195 GDOR+DSCT HD 181147 DSCT HD 50870 DSCT HD 170782 DSCT HD 170699 DSCT HD 44283 DSCT HD 172189 EA+SB 2+DSCT HD 181555 DSCT HD 49434 GDOR HD 171834 GDOR Evolutionary tracks calculated by Y. Lebreton and J. C. Suarez. Temperatures and Magnitudes calculated by P. Amado from Stromgren photometry. 34
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 HD 43587 UNEVOLVED : 3 4 5 6 HD 181147 HD 50870 HD 170782 HD 170699 8. 74 --8. 86 17 7. 81 197 6. 95 >200 HD 181555 HD 52265 HD 170580 ZIGZAGS (TAMS) 7 HD 44283 8 HD 172189 9. 29 8. 85 20 e Festival d'Astronomie de Haute 19 HD 43587 EA HD 171834 35
Target selection in the instability strip is based on the matching between theory and observation. Large experience from ground-based campaigns The investigations of Delta Sct stars are of course very preliminary. The frequency detection depend on the S/N. (Poretti, 2000) 36 (Garrido and Poretti 2004)
HD 44195, new DSCT star in the HD 43587 field Power spectrum showing variability 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 FOUND Unevolved : no dense frequency spectrum, no mixed modes Slow rotator : a relief for theoreticians, though progresses have been made in the treatment of fast rotators. 20 e Festival d'Astronomie de Haute 37
HD 44195, the hybrid GDOR + DSCT star v sin i = 58 km/s, in the field of HD 43587, f 1=20. 48 c/d The DSCT variability seems to be monoperiodic, The GDOR variability seems to be multiperiodic NOVEMBER 2003 (8 nights) 20 e Festival d'Astronomie de Haute JANUARY 2005 (4 nights) NOVEMBER 2005 (6 nights) 38
HD 44195 Hybrid variable, just one pulsation at high frequency. Power spectra from Stromgren photometry. Light curves from Mt Piszekesteto Observatory. 20 e Festival d'Astronomie de Haute 39
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 peaks around 10 and 20 c/d, (ampl. < 0. 003 mag in v) 20 e Festival d'Astronomie de Haute 40
HD 49434, confirmation of the light variability High precision photometry (s. d. better than 0. 002 mag) on four consecutive nights. Peak-to-peak amplitudes 0. 022 mag in violet 0. 019 mag in blue 0. 016 mag in yellow Multiperiodicity probable. Observations recently obtained (OSN, SPM and Mt. Piszekesteto) will be decisive to detect periodicities. Additional APT timeseries available. 20 e Festival d'Astronomie de Haute 41
HD 50870, a DSCT star in the field of HD 52265 f 1=17. 15 c/d f 2=14. 00 c/d ………. Slow rotator, Veq sin i = 17 km/s Predominant mode STEPHI campaign in November 2005 20 e Festival d'Astronomie de Haute 42
Field of HD 171834 HD 172189 : DSCT and eclipsing binary in the open cluster IC 4756 43
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 curve has been the goal of successful spectroscopic observations in past summer (OHP, SLN, ESO). Target of a STEPHI campaign in 2004. 20 e Festival d'Astronomie de Haute 44
HD 172189 not only an Eclipsing Binary, but probably also a Spectroscopic Binary (SB 2) FEROS spectrum, June 2004 45
HD 181555 – Candidate primary target Fast rotator : Vsin i > 200 Km/s Observed both at OSN and SPM. Evident multiperiodicity: set of frequencies in the 8 -11 c/d interval. 46
HD 180642, Beta Cep variable Monitored at SPM and OSN in Stromgren photometry, with Mercator telescope in the Geneva system and with M. Piszkesteto telescope in V filter Main pulsational frequency term identified as the Fundamental radial mode; additional terms 20 e Festival probable (Aertsdeet. Haute al. , in preparation) d'Astronomie 47
Reminiscent of the case of BW Vul (Sterken and coll. ) BW Vul HD 180642, Mercator and Mt. Piszkesteto light curves in V light 20 e Festival d'Astronomie de Haute 48
Target Type Field Frequencies V Sp V sin i HD 44195 hybrid HD 43587 HD 50870 DSCT HD 52265 HD 44283 DSCT HD 43587 f=20. 5 c/d f< 5 c/d f=17. 5 13 -15 f=15. 0 10 -25 7. 56 F 0 58 km/s 8. 88 F 0 17 km/s 9. 29 F 5 19 km/s HD 181147 DSCT HD 170782 DSCT HD 170699 DSCT HD 172189 DSCT HD 181555 DSCT f=15. 4 14 -17. 5 c/d 13 -25 c/d 10 -15 c/d 17 -19 c/d EA +SB 2 8 -18 c/d 8. 74 A 5 98 km/s 7. 81 A 2 197 km/s 6. 95 A 3 >200 km/s 8. 85 A 2 48 and 75 7. 98 A 5 170 km/s HD 181555 HD 170580 HD 171834 primary target HD 49434 GDOR HD 171834 GDOR photometric variability CONFIRMED 5. 75 F 1 90 km/s no photometric variability 5. 43 F 5 72 km/s HD 180642 BCEP HD 170580 BCEP HD 181555 f=5. 49 c/d, standstill 8. 29 B 1 37 km/s no photometric variability, multiple system 6. 68 B 2 V 20 e Festival d'Astronomie de Haute 49
OUTLINES THE MISSION The consortium, the persons, the satellite l The orbital plane, the observing modes l The scientific profiles l THE PREPARATORY WORK FOR ASTEROSEISMOLOGY Target selection in the Center and Anticenter directions l Target characterisation l Future activities l 50
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 20 e Festival d'Astronomie de Haute 51
The spectroscopic counterpart of the COROT observations 20 e Festival d'Astronomie de Haute FG Vir (Zima et al. 2006) 52
TARGETS FOR COORDINATED GROUND-SPACE OBSERVATIONS Preliminary list (ESO and OHP targets) P 78 IR 1 HD 50844 DSCT 9. 1 P 79 LRc 1 P 80 LRa 1 HD 180642 BCEP 8. 3 HD 49434 GDOR 5. 8 HD 181555 DSCT 8. 0 HD 50209 Be 8. 4 HD 181231 Be 8. 6 HD 49330 Be 8. 9 P 81 LRc 2 1° field HD 171834 GDOR 5. 4 HD 172189 DSCT 8. 8 2° field SR 1 (? ) HD 183324 LBOO 5. 8 HD 183656 Be 6. 1 HD 170580 HD 170699 HD 170782 HD 171219 BCEP DSCT Be SR 2 (? ) HD 175337 bona-fide. GDOR 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. 20 e Festival d'Astronomie de Haute 53 6. 7 6. 9 7. 8 7. 6
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, Co. Ro. T is offering us the possibility to improve rapidly our knowledge of stellar interiors. We have the possibility to consign a more But it’s challenging, and we like that. mature science to young researchers. 20 e Festival 54 d'Astronomie de Haute We are happy to be in the play, though it is
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