# Presentation: 261765

## JENNIFER SOBECK, FRANCESCA PRIMAS, CHRIS SNEDEN

**JENNIFER SOBECK, FRANCESCA PRIMAS, CHRIS SNEDEN**
- EUROPEAN ORGANIZATION FOR ASTRONOMICAL RESEARCH IN THE SOUTHERN HEMISPHERE
- AND
- THE UNIVERSITY OF TEXAS AT AUSTIN
- JULY 17, 2007

## GENERAL CHARACTERISTICS OF  COPPER 

-  **Two Isoptopes: ****63****Cu (69.17%), ****65****Cu (30.83%)**
** ****Presence of hyperfine structure (I = 3/2)**
** ****Solar photospheric abundance: log ********Cu**** = 4.21 ± 0.04 (Anders & Grevesse 1989)**
** ****CI meteoritic abundance: log ********Cu**** = 4.23 ± 0.06 (Lodders 2003)**
** ****76 optical spectral transitions**

-  Primary synthesis mechanisms: weak s-process and explosive nucleosynthesis (note that minimal contribution occurs from main s-process: approximately 5%; Travaglio et al.2004)

- Shared Upper Level

## OBSERVATIONAL DATA AND THEORETICAL PREDICTIONS FOR Cu ABUNDANCE 

**OBSERVATIONAL DATA AND THEORETICAL PREDICTIONS FOR Cu ABUNDANCE **

-  LEFT PANEL: Spectroscopic observations of [Cu/Fe] as a function of [Fe/H] for field stars in the Halo, thick-disk, thin-disk, Bulge-like stars and Omega Cen
-  RIGHT PANEL: Long-dashed line indicates Mej (Cu-weak s), Mej (Cu-SNe II), and Mej (Cu-SNe Ia) from Matteucci et al. 1993; short-dashed line is analogous with the exception of
- Mej (Cu-SNe Ia) from Iwamoto et al. (1999); and dotted line signifies removal of Type II SN contribution

- Bisterzo et al. 2005, Nuc. Phys A, 758, 284 ; Romano & Matteucci, MNRAS, 378, L59

## THEORETICAL PREDICTIONS FOR Cu ABUNDANCE 

**THEORETICAL PREDICTIONS FOR Cu ABUNDANCE **

-  CONCLUSION: Trend in the solar vicinity well-reproduced; metallicity-dependent yield
-  CONCLUSION: Initial, primary contribution originates from core collapse SNe and secondary contribution arises from the weak s-process in massive stars
-   ODDITY: Decline of [Cu/Fe] as a function of [Fe/H] due to reduced extent of weak s-process in massive stars at low [Fe/H] OR the delayed production from Type Ia SNe

- Romano & Matteucci, MNRAS, 378, L59

## PRIMARY MOTIVATIONS FOR NEW INVESTIGATION 

-  Completion of original study by Primas et al. reconciliation of abundances derived from ultraviolet and visible wavelength transitions.

-  Expansion of data set to include newly-available spectra from a variety metal-poor star survey programs

## RELEVANT ATOMIC PARAMETERS FOR Cu TRANSITIONS  

- REVISIONS TO THE ATOMIC PARAMETERS INCLUDE:
**HYPERFINE STRUCTURE (REFERENCE: Hermann et al. 1993)**
**ISOTOPIC SHIFT (REFERENCE: Hermann et al. 1993)**
**OSCILLATOR STRENGTHS (REFERENCE: Curtis & Theodosiou 1989) **

- ULTRAVIOLET-
- 3247.54 Å ( = 0.00 eV; log (gf) = -0.048) *presence of contaminant
- 3273.96 Å ( = 0.00 eV; log (gf) = -0.353)
- OPTICAL -
- 5105.54 Å ( = 1.39 eV; log (gf) = -1.52)
- 5782.13 Å ( = 1.64 eV; log (gf) = -1.72)

- *CRITICAL COMPILATION OF TRANSITION PROBABILITY DATA: Fu et al. 1995, At. Data & Nuc. Tables, 61, 1

## HYPERFINE STRUCTURE OF THE Cu D1 AND D2 RESONANCE LINES 

-  3247.54 Å FEATURE

-  3273.96 Å FEATURE

## SPECTRAL SYNTHESIS OF THE ULTRAVIOLET TRANSITIONS  

-  Cu TRANSITION 3273.96 Å

-  Cu TRANSITION 3247.54 Å

- Ti II

- Fe I

- Fe I, II

- Multiple: Fe I, Eu II, ...

- * Note that OH also has several transitions in this wavelength regime

## SPECIAL CONSIDERATIONS   

- Rayleigh scattering must be taken into account in the ultraviolet spectral range for low temperature, low surface gravity metal-poor stars

-  The spectral synthesis program MOOG was altered accordingly to incorporate a source function which is a summation of an absorption and a scattering component (***S =****** ************B + (1 − ************)J***).  The Short Characteristics Methodology was used in the line transfer solution.

## DATA SET DESCRIPTION AND STELLAR ATMOSPHERIC MODEL PARAMETERS  

** **DATA SAMPLE SIZE: NSTARS = 50
-  DETECTOR/INSTRUMENT SET-UP: ESO VLT 8m Kueyen Telescope with the Ultraviolet and Visual Echelle Spectrograph (UVES)
-  TEMPERATURE RANGE: 5530 ≤ Teff ≤ 6475 K
-  SURFACE GRAVITY RANGE: 3.7 < log(g) < 4.6
-  METALLCITY RANGE: -3.3 ≤ [Fe/H] ≤ -0.5
-  SIGNAL TO NOISE RANGE: 80 ≤ S/N ≤ 150 (UV); 250 ≤ S/N ≤ 500 (Visible)
-  RESOLUTION: R (/) = 45,000-50,000

## Cu ABUNDANCE AS A FUNCTION OF METALLICITY  

-  UPPER PANEL: [Cu/Fe] as a function of [Fe/H] taken solely from the 3274 Å transition (scaling factor for least metal-poor targets)
-  MIDDLE PANEL: Inclusion of abundance due to the feature at 3247 Å
-  LOWER PANEL: Addition of data from the 5782 Å  line

## Cu ABUNDANCE AS A FUNCTION OF STELLAR ATMOSPHERIC PARAMETERS  

##  Extension of abundance determination to the infrared (viable transitions present beyond  = 7000 Å) 

-  Improvement of branching fraction determination (and consequently, oscillator strength) for the visible wavelength transitions
-  Inclusion of more abundances derived from the visible spectral features and expansion of the comparison between the [Cu/Fe]3274 Å and [Cu/Fe]5105 Å, 5782 Å values
-  **Completion of analysis of original data set which includes spectra from extremely metal-poor stars ([Fe/H] < -2.8)!**
-  Extension of abundance determination to the infrared (viable transitions present beyond  = 7000 Å)
-  Comparison to other Cu abundance surveys (e.g. Simmerer et al. 2004, Mishenina et al. 2002, ...)
-  Determination of Zn abundances and correlation to Cu values
-  Further elucidation of the nucleosynthesis mechanism (theoretical predictions)