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Tautenburg planet search program Eike Guenther Artie Hatzes Davide Gandolfi Michael Hartmann Massimiliano Esposito (now Hamburger Sternwarte) Felice Cusano Michaela Döllinger (ESO) Eike Guenther Artie Hatzes Davide Gandolfi Michael Hartmann Massimiliano Esposito (now Hamburger Sternwarte) Felice Cusano Michaela Döllinger (ESO)
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I. Planets of young stars Eike Guenther Massimiliano Esposito Eike Guenther Massimiliano Esposito
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The orbits of exo-planets are as eccentric as those of binaries
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-Many short- period planets... -..but is there a lack of very massive ones?
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Question: What fraction of close- in planets were destroyed in the first 10-100 Myr ? Close-in planets can be destroyed by: Evaporation Tidal interaction between the planet and the host star Planet-planet interaction Close-in planets can be destroyed by: Evaporation Tidal interaction between the planet and the host star Planet-planet interaction
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Weidenschilling & Marzari 1996 Nature 384, 19 Planet-planet interaction might play in important role in shaping planetary systems
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Planets of young stars What is the frequency of massive, close-in planets? Are the orbits eccentric or round? Studying interaction of planets and disks What is the frequency of massive, close-in planets? Are the orbits eccentric or round? Studying interaction of planets and disks
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Precise RV-measurements using the iodine cell
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Young stars are active and spots cause RV-variations
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How can we distinguish planets and activity? Spots change in time: long time basis Bisectors CaH,K, and other chrosmospheric lines photometry Spots change in time: long time basis Bisectors CaH,K, and other chrosmospheric lines photometry
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How active are the stars?
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Tautenburg Survey Survey started Feb 6, 2001 Age 30..300 Myr 43 stars (some stars removed that were not young) SpecTyp G,K,M >2000 spectra Survey started Feb 6, 2001 Age 30..300 Myr 43 stars (some stars removed that were not young) SpecTyp G,K,M >2000 spectra
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Detection limits: a few examples 50%100% 10% σ RV = 14.4 m/s N p = 48 σ RV = 11.3 m/s N p = 20σ RV = 10.5 m/s N p = 10 100% 50% 10% σ RV = 139 m/s N p = 68
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Lithium as age indicator TLS sample
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HARPS survey Age 10..100 Myr (TW Hydra, beta Pic, Horologium, Tucana, IC2391) 85 stars SpecTyp G,K,M Ongoing since 2004 Age 10..100 Myr (TW Hydra, beta Pic, Horologium, Tucana, IC2391) 85 stars SpecTyp G,K,M Ongoing since 2004
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A spin off: binaries for testing the evolutionary tracks with the VLTI
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THIS IS NOT A PLANET! K = 51.3 m/s ; e @ 0 ; MPsin(i) = 0.30 MJ ; a = 0.024 AU
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Planets (candidates) I
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Planets (candidates) II
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Be careful !!! Young stars are active, from the fact that all the data phases up one should not conclude that this is a planet! -- What we do now : photometry with REM -- Spectroscopy with CRIRES (RV caused by activity depends on wavelength) Young stars are active, from the fact that all the data phases up one should not conclude that this is a planet! -- What we do now : photometry with REM -- Spectroscopy with CRIRES (RV caused by activity depends on wavelength)
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NAHUALNAHUAL A high-resolution infrared spectrograph for planet hunting
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Results TLS survey: 8 SBs 0 planets For 80% of the stars we can exclude M>2M Jup and period>10 days. For 95% of the stars we can exclude M>7M Jup for periods < 10 days 8 SBs 0 planets For 80% of the stars we can exclude M>2M Jup and period>10 days. For 95% of the stars we can exclude M>7M Jup for periods < 10 days
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Detection limits:results 35 stars Percentage of stars without planets
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Results HARPS survey: Sample: 85 stars (originally 92 but 7 are not young) 5 SBs Only one planet candidate! Again: no massive (M>> 1 Mj), close-in planets! Sample: 85 stars (originally 92 but 7 are not young) 5 SBs Only one planet candidate! Again: no massive (M>> 1 Mj), close-in planets!
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Conclusions The frequency of close-in, massive planets of stars with an age of 10 to 300 Myr is about the same as that of old stars. --> At least not man very massive, close- in planets were destroyed in the age between 10 and 100 Myr. They were either destroyed at an earlier age, or never formed.
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Planets of giant stars (PhD thesis Michaela Döllinger) Giant stars are cool and have a low vsini. Problem I: giant stars have oscillations Problem II: mass-determination Giant stars are cool and have a low vsini. Problem I: giant stars have oscillations Problem II: mass-determination
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Mass determination of giant stars (F Cusano, E.Guenther, A. Hatzes, CHARA Team) First step: How good are the models from stellar atmospheres? Compare true diameters derived with CHARA with those derived from spectroscopic observations Answer: TrueDiameter * (1.08+/-0.15)=SpecDiameter First step: How good are the models from stellar atmospheres? Compare true diameters derived with CHARA with those derived from spectroscopic observations Answer: TrueDiameter * (1.08+/-0.15)=SpecDiameter
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HD13189 (mass of star: 3.5 Msun, msini of planet: 14 +/- 0.8 M Jup )
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Pollux (mass of star. 1.7 M sun ; msini of planet: 2.3 M Jup )
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Results - massive stars of low metalicity can also have planets -the frequency of planets more massive than the sun could be as high as 25%
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III. Planets of F-stars: (1.1-1.7 M sun ) 30 Ari A binary 30 Ari B has planet with orbital period of 327 days, and a mass of about 10 M Jup 30 Ari A binary 30 Ari B has planet with orbital period of 327 days, and a mass of about 10 M Jup
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IV. CoRoT Convection, Rotation, Transits CNES (France), ESA, Germany, Spain, Belgium, Austria, Brazil Telescope: 27 cm aperture, inclined mirrors, 4.2m long, 270 kg. Live time > 2.5 years Optimized for ultra-high precision photometry FOW 1.4x2.8 degrees Observes fields continuously for 150 days Convection, Rotation, Transits CNES (France), ESA, Germany, Spain, Belgium, Austria, Brazil Telescope: 27 cm aperture, inclined mirrors, 4.2m long, 270 kg. Live time > 2.5 years Optimized for ultra-high precision photometry FOW 1.4x2.8 degrees Observes fields continuously for 150 days
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