Stellar Abundances
Playing around with abundances in the quasar absorption line systems
means one is constantly comparing with Galactic stellar abundances.
It didn't take long for me to become quite interested in the latter. Decided
I might dabble in stellar spectroscopy during twilight hours at Keck.
On the left is an example of the quality of data one can obtain in 5 minutes.
That dotted green line is the error array.
Pretty amazing...
My only stellar observational project to date has been on the abundance
patterns of thick disk stars. For those of you familiar with my damped
Lya reserach, this probably will not be a big
surprise. Have been quite amazed at the similarities of the kinematics
of the two and have wondered if the abundances show any similiarities.
There has been some research on the thick disk stars, but not much and nothing
on Zn which is such an important element in damped Lya
studies. Have learned a ton about the stellar business; in particular from
the maestro A. McWilliam. I had always assumed that the stellar guys were
worlds ahead of our simple QAL abundance studies. Can't say I'm of that
opinion anymore. If you disagree with me, check out what the head honcho
himself has to say: Kurucz.
Along the way, A. McWilliam and I decided to write up a Letter on the perils of hyperfine splitting in stellar abundance analysis. In the case of a recent Mn and Sc analysis, it has a quite a significant effect..
On the Perils of Hyperfine Splitting:
A reanalysis of Mn and Sc abundance trends; Prochaska & McWilliam 2000,
ApJ, 537, 57L
Just completed my first analysis on the thick disk stars. What a bear and it was only 10 stars. The figure above summarizes some of the results for the Alpha elements. There are some intriguing results including the prospect that the thick disk and bulge shared a similar origin. You'll have to grab the paper to get the full scoop.
The Galactic Thick Disk Stellar Abundances; Prochaska, Naumov, Carney, McWilliam, & Wolfe 2000, AJ, in press
Tables8-17.ps.gz
Tables8-17.tex
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modified 10/23/00