1 / 39

Abundance analysis on Late G giants — 59 stars of Xinglong Planet search sample

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

eaton-fulton
Download Presentation

Abundance analysis on Late G giants — 59 stars of Xinglong Planet search sample

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 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.,

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

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

  4. Host Stars’ Metallicity--giants • About 20 candidates around giants, more than half of them are under solar metallicity • Pasquini et al. 2007 blue line- 14 giants red dashed line--dwarfs The giants show a distribution shifted to lower metallicity by about 0.2-0.3 dex with respect to the dwarf.

  5. Takeda et al. 2008 Since the small number of detected planets around giants, this statistics results remain unclear.

  6. Lack of giants with [Fe/H] > 0.2 Soubiran et al. 2008 (891 sample) Takeda et al. 2008 (322 sample) Metallicity distribution of thin disk clump giants of the local (filled) and distant sample (red line)

  7. Red giants Branch 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. • CNO cycle: C decrease N increase O decrease or unchanged • NaNe cycle: Na increase

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

  9. Luck et al. 2007-298 giants • C depleted • O unaffected

  10. 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)

  11. Observational Data • Sample selection B-V: 0.6-1.0 Mv: -3 -- 2.5 V: 6 δ: >-20° • Data Observation HIDES attached to OAO R=67000 wavelength coverage: 44 stars 5000-6200 15 stars 4000-7500 S/N: 100-250

  12. 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

  13. Stellar Parameters-Teff • 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

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

  15. Stellar Parameters-logg • Surface gravity log(g/g⊙) = log(M/M⊙) + 4 log(Teff/Teff⊙) + 0.4(Mbol - Mbol⊙) where：Mbol = V + BC- 5 logπ + 5-Av Av = 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

  16. Stellar Parameters-Vt • 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 Teff, 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.

  17. Ionization equilibrium test

  18. Ionization equilibrium test

  19. stellar parameter consistency check with literatures ◊ Brown et al. 1989 (7 stars) ○ Mishenina et al. 2006 (4 stars) ∆ Luck et al. 2007 (4 stars)

  20. [Fe/H] 0.05 dex higher than literature

  21. Stellar parameters with Takeda 2008

  22. Stellar parameters with Takeda 2008

  23. Stellar parameters with Takeda 2008

  24. Error analysis(HD47366, Teff=4834,logg=2.76,vt=1.3,[Fe/H]=-0.01)

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

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

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

  28. Abundance Analysis O5577-- O6300 [O/Fe]6300= 0.08±0.05 dex + [O/Fe]5577

  29. CarbonOxygen C depleted O remain unaffected

  30. Sodium Na overabundance 0.1 dex

  31. C,O,Na with Mass

  32. Si,Ca

  33. Ti, Cr

  34. Ni, Mn

  35. Ce,Y

  36. Sc

  37. Remind problems • Abundance from O 5057 maybe not correct

  38. 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

  39. Welcome to Xinglong!

More Related