Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Spectroscopic characteristics of planet-host stars and their planets Nuno C. Santos (Observatory of Lisbon, Portugal & Geneva Observatory, Switzerland)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 The problem: strange new worlds ● Currently ~120 exoplanets are known ● Difficulty in explaining orbital properties and masses ● How do giant planets form? Need to revise theories of planet formation and evolution

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 How to do it? ● Statistical properties of exoplanets (mass, eccentricity, orbital period,...) (e.g. Udry et al. 2003; Zucker & Mazeh ; Eggenberger et al. 2004) ● Information from the planet-host stars (abundances, rotation, kinematics,...) (e.g. Gonzalez , Barnes et al. 2002; Santos et al )

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Clues from the chemical properties of planet host stars ● Planet host stars are very metal-rich!!! (e.g. Gonzalez et al ; Santos et al ) ● How to explain this fact? ● What is this telling us about the planetary formation processes?

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Spectroscopic analysis and samples ● Result of uniform comparison of 2 samples: – 98 planet-hosts (Santos et al. 2004) – Compared with stars within a limited volume – Same line-lists, atmosphere models,... ● Similar comparisons done by several authors (e.g. Reid 2002; Laws et al. 2003)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Average difference 0.25dex Clearly distinctive samples - P(KS)~10 -9 Santos et al. 2004

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Metallicity of planet-hosts ● Difference is clearly significant! ● Independ. of method to derive stellar parameters (e.g. Gonzalez ; Gimenez 2000; Santos et al. 2004) ● Not explainable by observational biases: – No (major) metallicity based samples – No effect due to precision of RV surveys (Santos et al. 2003; Fischer et al. 2003)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 This is not an artifact of the RV technique Santos et al. (2003) Fischer et al. (2003)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 The origin of the high-[Fe/H] ● ''Primordial'' origin: to form (these) planets you need metals (e.g. Santos et al. 2001, 2003) ● ''Stellar pollution'': infall of planetary material into stellar conv. envelope (e.g. Gonzalez 1998, Murray 2002) How can we distinguish?

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Using the convective envelope No Correlation! Pinsonneault et al. (2001) Santos et al. (2003)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Arguments for “Primordial” origin ● No trend in the [Fe/H] vs. M conv plot ● Sub-giants with planets also very metal-rich – e.g. HD38529 ([Fe/H]=+0.40); HD27442 ([Fe/H]=+0.39) ● K dwarfs with planets also metal-rich – e.g. HD75732 ([Fe/H]=+0.33); 14 Her ([Fe/H]=+0.43)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Probability of finding planet [Fe/H]=0.0 →~3% ; [Fe/H]=0.3 →~25% (Santos et al. 2001, 2003, 2004; Reid et al. 2002; Fischer et al. 2003)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Implications for models: Core accretion vs. disk instability ● Core accretion model: planet formation dependent on dust content (e.g. Pollack et al. 1996; Alibert et al. 2004) ● Disk instability model: not strongly dependent on metallicity (Boss 2002) Observations are (more) compatible with core accretion model!

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Two different populations or a flat tail? Santos et al. (2004)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 “Pollution” not generalized but... ● Some evidences for stellar “pollution” events (Gonzalez 1999; Laws 2002; Murray et al. 2002) ● 6 Li in HD82943: – Not survive PMS evolution – probably best example (Israelian et al. 2001, 2003)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July Li in the metal-rich planet-host HD82943 (G0V)! Israelian, Santos, Mayor, Rebolo (2001, 2003)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 How to explain? ● Not original ● Not produced (flares?) ● External source is best explanation! – Planets and/or planetary material! ● Not enough to explain excess [Fe/H]

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Studies of other elements ● Confirm that the metal excess is global ● Look for trends: – Do planet hosts follow Galactic chemical evolution trends? – Condensation temperature dependence?

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Iron-peek and alpha- elements Bodaghee et al Sadakane et al. 2002

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Iron-peek and alpha- elements Bodaghee et al Sadakane et al. 2002

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 C, N, S,... (Ecuvillon et al. 2004) See poster by Ecuvillon et al. on C, N, O, Zn, and Cu For other elements: Zn, Cu (Ecuvillon et al. 2004), Na, Mg, Al (Beirao et al. 2004)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 General conclusion: ● Similar enrichment for all elements (in the range dex) ● Volatiles (N, C, O,...) not distinctively different from reflactories ● Abundances follow “normal” Galactic evolution trends

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Light Elements ( 7 Li and 9 Be) ● Good tools to look for stellar “pollution”... ●... and stellar mixing (rotational history?) ● Are Li and Be abundances in planet-hosts different? (Reddy 2000; Gonzalez et al. 2000)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Lithium in planet- host stars (Israelian et al. 2004)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Comparison with Chen et al. (2001) sample Planet-hosts: low Li for T eff between K? (Israelian et al. 2004)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Beryllium in planet- hosts: no clear difference Santos et al. (2004)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Models with rotational induced mixing (Pinsonneault et al. 1990) Santos et al. (2004)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Internal-wave physics? (Montalban et al. 2000) Santos et al. (2004)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Be. gap for solar temperature stars! Santos et al. (2004)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Conclusions ● General metallicity excess in planet-hosts ● Primordial origin ● Probability of planet-formation strongly depends on metallicity – Strong support core-accretion scenario as primary planet formation mechanism

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Open issues... ● What is precisely the P([Fe/H])? ● Light elements (Li and Be): some interesting trends – Lower Li for solar temp. stars with planets? (Israelian et al. 2004) ● How important are pollution events? ● Planets and stellar mass? (Santos et al. 2003; Laws et al. 2003) ● Orbital parameters and stellar metallicity? (Gonzalez 1998; Queloz et al. 2000; Santos et al. 2003; Laws et al. 2003) Poster by Udry, Mayor & Santos

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 What about the planets? ● Currently we cannot resolve the planet ● Transiting planets: – possibility to study the planet itself ● First transiting planet around HD209458b: – Optical spectroscopy - detection of Na (Charbonneau et al. 2000)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Spectroscopy of HD209458b ● UV spectroscopy: detection of H, C, and O: exosphere! (Vidal-Majar et al. 2003, 2004) ● Planet evaporating!

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 OGLE candidates! OGLE-TR-113 e 132 ● P=1.43 and 1.69 days ● M=1.35 and ~1.0 M(Jup) Bouchy et al. (2004)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Prospects... ● More and more transits are needed... ● Around “bright stars” ● Space missions like COROT, etc... ● Spectroscopy of hot-jupiters with the VLTi (Segransan et al. 2000)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 THE END

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Density of planet depends on orbital radius? (see poster by Udry et al.) Bouchy et al. (2004)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004

6 Li in HD82943: stellar pollution! Israelian, Santos, Mayor, Rebolo (2001, 2003)

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Metallicity and Orbital Period

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Metallicity and Planetary mass

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Metallicity and eccentricity

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Stellar mass vs. [Fe/H]

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Planets and U,V,W

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Planets and U,V,W, [Fe/H]

Nuno C. Santos Cool Stars 13 - Hamburg, Germany - July2004 Be. vs. T eff How to explain trend? Santos et al. (2004)