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Abundance Patterns to Probe Stellar Nucleosynthesis and Chemical Evolution. Francesca Primas. Setting the Stage. 1. High-z universe, i.e. looking at objects in their infancy stages. DLA: dominant reservoir of neutral baryons measure the mean metallicity in HI (5< z < 0).

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setting the stage
Setting the Stage

1. High-z universe, i.e. looking at objects in their infancy stages

  • DLA: dominant reservoir of neutral baryons
  • measure the mean metallicity in HI (5< z < 0)

2. Nearby universe, i.e. looking at the fossilized imprint left by the first generations of stars

  • EMP: precious witnesses of the early evolutionary phases of our Galaxy

Identify the imprint left by the first SNe explosions

Old

Metal-poor

[Fe/H] = log(Fe/H)* - log(Fe/H)sun

stellar nucleosynthesis
Stellar Nucleosynthesis

light elements

BBN, CR spallation

alpha and iron-group

SN physics (time delays) and SN imprint

heavies

n-capture

the light elements
The Light Elements

Li Be B

(670.7nm, 313.0nm, 250.0nm)

  • Implications for cosmology

BBN vs IBBN (Li)

  • Implications for stellar structure

Li T=2.5x106K

Be T=3.0x106K

B T=5.0x106K

  • Implications for nucleosynthesis and cosmic-ray physics

classical spallation (Reeves et al. 1970) ?

primary ? neutrino-spallation (11B) ?

what have we learned
What Have We Learned
  • well defined trends with low dispersion all the way to the most MP stars
  • as quality , the dispersion 
  • -- SMALL in most cases: 0.05-0.15dex
  • -- THINNEST of all: Cr,Ti
  • -- MOST DISPERSED: Mn (~0.2dex for [Fe/H]<-3)
  • there is NO unambiguous detection of products of PISN
  • constraints on SN II yields: M~15-50 Msun, but also up to 100Msun or hypernovae are able to reproduce the observed
  • trends (mixing and fallback)

Abundancedispersion s=0.05dex!

Cayrel et al. (2004) data

stellar highlights
Stellar Highlights

HE 0107-5240 ([Fe/H]=-5.3)and HE 1327-2326 ([Fe/H]=-5.5

(large[C/Fe], but different in N, Na, Mg, Al)

C-rich metal-poor stars: 20-30% (?)

r-process rich stars

the detailed picture
The Detailed Picture

CS 22892-052

Sneden et al. 2003

CS 31082-001

Hill et al. 2002

Galaxy at z=2.63

Prochaska et al. 2003

slide9

Hill et al. 2002

1. Does Os really deviate from the solar r-process pattern ?

Not anymore after new gf value (Ivarsson et al. 2003) ==> Os=Ir

2. Still missing input atomic physics for Ho, Lu, and Yb!

what s next
What’s next ?

--->Atomic physics and (best) abundance

indicators

--->Model atmospheres and theory of line

formation

LTE vs NLTE

1D vs 3D

Asplund 2005 (ARAA)

Asplund 2002

1d vs 3d
1D vs 3D

CNO Fe

Collet et al 2006

cosmo chronometry
Cosmo-chronometry

EMP = old ?? Not quite, presumably old ==> age

In r-process rich stars:

Dt = 46.67(log(Th/S)o - log(Th/S)obs )

Problem: evaluation of the log(Th/S)o based on the

assumption that the r-process is universal

[ cf. Cowan (pro) and Goriely (con) ]

Warning: actinides and lower-mass r-nuclei may vary strongly (despite the constancy for Z=56-82)

[ cf. Hill et al. 2002, Honda et al. 2003]

Th (and U) seem to be over-abundant:

log(Th/Eu) = -0.22 (wrt ~ -0.6! for similar stars)

cosmo chronometry1
Cosmo-chronometry

Age difference ?NO, otherwise CS 31082-001 would have a

negative age, compared to the other n-rich stars !

Ab initio enhancement ?IF SO, r-process may not be universal !

Th/Eu =? a reliable chronometer

CS 31082-001:Th and U were detected and used

Dt = 21.76(log(U/Th)o - log(U/Th)obs)

+similar ionization and excitation potentials --> errors largely cancel out

+ initial production ratio: more robust against variations in n-exposure

(nuclear reaction network code containing more than 3500 isotopes with all relevant reactions! )

Nilsson et al. 2002a,b

Goriely & Arnould 2001

!

8 Th lines, each with gf determined better than 0.08dex

1 U line with gf determined better than 0.06dex

log(U/Th)o = 0.50 (0.02)

Age = 14.0 +/- 2.4 Gyr

log(U/Th)obs = -0.74 (0.15) … -0.94 (0.11)