Observational evidence for a broken Li Spite plateau and mass-dependent Li depletion

Details Observational evidence for a broken Li Spite plateau and mass-dependent Li depletion Observational evidence for a broken Li Spite plateau and mass-dependent Li depletion

2010-05-17

arxiv.org/abs/1005.2944v1

Astronomy and Astrophysics

Astrophysics

Solar and Stellar Astrophysics

A&A Letters, in press

Scientific paper

We present NLTE Li abundances for 88 stars in the metallicity range -3.5 < [Fe/H] < -1.0. The effective temperatures are based on the infrared flux method with improved E(B-V) values obtained mostly from interstellar NaI D lines. The Li abundances were derived through MARCS models and high-quality UVES+VLT, HIRES+Keck and FIES+NOT spectra, and complemented with reliable equivalent widths from the literature. The less-depleted stars with [Fe/H] < -2.5 and [Fe/H] > -2.5 fall into two well-defined plateaus of A_{Li} = 2.18 (sigma = 0.04) and A_{Li} = 2.27 (sigma = 0.05), respectively. We show that the two plateaus are flat, unlike previous claims for a steep monotonic decrease in Li abundances with decreasing metallicities. At all metallicities we uncover a fine-structure in the Li abundances of Spite plateau stars, which we trace to Li depletion that depends on both metallicity and mass. Models including atomic diffusion and turbulent mixing seem to reproduce the observed Li depletion assuming a primordial Li abundance A_{Li} = 2.64, which agrees well with current predictions (A_{Li} = 2.72) from standard Big Bang nucleosynthesis. Adopting the Kurucz overshooting model atmospheres increases the Li abundance by +0.08 dex to A_{Li} = 2.72, which perfectly agrees with BBN+WMAP.

Affiliated with

Also associated with

No associations

Rating

Observational evidence for a broken Li Spite plateau and mass-dependent Li depletion does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Observational evidence for a broken Li Spite plateau and mass-dependent Li depletion, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Observational evidence for a broken Li Spite plateau and mass-dependent Li depletion will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-299022