Abundance analysis on Late G giants — 59 stars of Xinglong Planet search sample Yujuan Liu( 劉玉娟 ) NAOC/NAOJ Ando H., G. Zhao, Sato Bun’ei, Takeda Y.,

Contents Introduction of purpose of this work Sample observation and reduction Stellar parameters and kinematic parameters Surface chemical compositions analysis

Host Stars’ Metallicity--dwarf  More planets around more metal-rich stars  No planets around metal-poor (-2<[Fe/H]<-0.8) stars so far Fisher et al. 2005

Host Stars’ Metallicity--giants About 20 candidates around giants, more than half of them are under solar metallicity Pasquini et al blue line- 14 giants red dashed line--dwarfs The giants show a distribution shifted to lower metallicity by about dex with respect to the dwarf.

Takeda et al Since the small number of detected planets around giants, this statistics results remain unclear.

Lack of giants with [Fe/H] > 0.2 Soubiran et al (891 sample) Takeda et al (322 sample) Metallicity distribution of thin disk clump giants of the local (filled) and distant sample (red line)

Red giants Branch CNO cycle: C decrease N increase O decrease or unchanged NaNe cycle: Na increase When the star moves towards RGB, the nucleosynthesis products penetrate into the atmosphere due to first dredge-up phase, changing the surface abundance of Li, C, N, O and Na. The effect depends both on the stellar mass and metallicity.

Mishenina et al. (2006)- 177 RCG Na C deplete 0.28 dex N overabundance 0.21 dex O no change Na overabundance 0.1dex

Luck et al giants C depleted O unaffected

Purpose of this work Establish stellar parameters and kinematic parameters Determine surface chemical compositions, focusing on C, O, Na Find super metal-rich stars ([Fe/H]>0.2)

Observational Data  Sample selection B-V: M v : V: 6 δ: >-20°  Data Observation HIDES attached to OAO R=67000 wavelength coverage: 44 stars stars S/N:

Data reduction  IRAF: bias subtraction, flat-fielding, scattered-light subtraction, spectrum extraction, wavelength calibration, continuum normalization  EW: fitting by a Gaussion function--SPSHOW program developed by Takeda et al. 2005

Stellar Parameters-T eff  Effective temperature – (B-V) color index and [Fe/H] from empirical calibration of Alonso et al. (1999)  E(B-V)s --Schlegel et al. (1998) For nearby stars

Stellar Parameters-Teff E(B-V) can be acceptable

Stellar Parameters-logg  Surface gravity log(g/g ⊙ ) = log(M/M ⊙ ) + 4 log(Teff/Teff ⊙ ) + 0.4(Mbol - Mbol ⊙ ) where ： M bol = V + BC - 5 logπ + 5-Av A v = 3.1E(B-V) Mass– evolution track of Yonsei-Yale (Yi et al. 2003) within 0.3 M ⊙ difference with those from Giradi (2000)---Liu et al. 2007

Stellar Parameters-V t  Microturbulent velocities were calibrated by forcing different Fe I lines with 10< EW <120 mÅ give a uniform iron abundance value.  Finally, the whole procedure of determination of T eff, logg and metallicity was repeated until the final metallcity from the equivalent width calculation was full consistency with input [Fe/H] within 0.01 dex.

Ionization equilibrium test

◊ Brown et al (7 stars) ○ Mishenina et al (4 stars) ∆ Luck et al (4 stars) stellar parameter consistency check with literatures

[Fe/H] 0.05 dex higher than literature

Stellar parameters with Takeda 2008

Error analysis( HD47366, Teff=4834,logg=2.76,vt=1.3,[Fe/H]=-0.01 ) Δ T eff (+100K) Δ Logg (0.1) Δ[Fe/H] (0.1) Δv t (0.3kms-1) tot Δ[Fe/H] Δ[Fe/H] II Δ[C/Fe II ] Δ[O/Fe] Δ[Na/Fe] Δ[Si/Fe] Δ[Ca/Fe] Δ[Ti/Fe] Δ[Cr/Fe] Δ[Ni/Fe] Δ[Y/Fe] II

Kinematic parameters Most stars belong to thin disk. Thick disk stars—higher eccentricity

Thick disk stars—higher space velocity —low mass (old stars)

● O 6363 Δ O 5557 Abundance Analysis [O/Fe] 6300 = -0.02±0.04 dex + [O/Fe] 6363

Abundance Analysis O O6300 [O/Fe] 6300 = 0.08±0.05 dex + [O/Fe] 5577

Carbon Oxygen C depleted O remain unaffected

Sodium Na overabundance 0.1 dex

C,O,Na with Mass

Si,Ca

Ti, Cr

Ni, Mn

Ce,Y

Sc

Remind problems  Abundance from O 5057 maybe not correct

Conclusion  Stellar parameter lie in the main group of Takeda et al. 2008, lack of stars [Fe/H]>0.2  Most sample belong to thin disk stars  C depleted 0.13 dex(-0.1<[Fe/H]<0.1)  O remain unaffected  Na overabundance 0.1 dex The effect dependt on [Fe/H] and Mass.  Other elements remain unaffected, consisting with results of Takeda et al. (2008) Consist with theoretical results