Bob Parsons Alberta wrote:Yup congrats. How is the wine buying coming along in SD?
The week before this past I got word that a first author paper of mine was accepted for publication,
Jim Cassidy wrote:What does the paper say? (Please remember my uneasy relationship with physics ...)
WIYN Open Cluster Study LVII: Oxygen Abundances of Solar-Type Dwarfs in the Hyades and NGC 752
Oxygen has been proposed as a superior tracer, compared to iron, for studying galactic chemical evolution. In the context of improving our understanding of the evolution of Galactic oxygen using open clusters, we present a spectroscopic analysis of oxygen and iron abundances in the 650 Myr old Hyades cluster and in the 1.45 Gyr old cluster NGC 752, using high-dispersion 7774A O I triplet region spectra of dwarfs in these clusters acquired with the Hydra MOS on the WIYN 3.5-meter telescope. Motivated by recent improvements in analysis of the triplet, we use a strictly differential analysis in solar-type stars to obtain reliable O abundances. Using stars whose radial velocities and spectral cross-correlation analyses are consistent with single-star membership, we report Hyades cluster averages of [O/H] = 0.195 +/- 0.010 and [Fe/H] = 0.130 +/- 0.009 based on 22 stars, and NGC 752 cluster averages of [O/H] = -0.077 +/- 0.02 and [Fe/H] = -0.063 +/- 0.013 based on 36 stars (where the errors are the standard deviation of the mean; we discuss possible additional systematic errors). These cluster abundance averages are in very good agreement with most previous determinations. Whereas the [O/H] cluster averages utilize only stars found in the ``prime'' temperature range straddling the solar temperature, the [Fe/H] cluster averages come from stars exhibiting a flat [Fe/H]-T relation of over 1000K for the Hyades and nearly 2000K for NGC 752. Previous studies of open clusters younger than NGC 752 have reported oxygen triplet over-abundances in cool dwarfs, as compared to oxygen abundances of the prime-T range. We report that NGC 752 also shows such overabundances, at a higher level than the Hyades overabundances, and thus contradicts the idea of a decline of such overabundances with increasing age. We discuss evidence for and against correlations of the oxygen-overabundances with rotation, X-ray luminosity, chromospheric activity, and metallicity.
In particular, we wanted to investigate a previous finding (an unpublished dissertation) that young clusters have elevated oxygen abundances. This paper supports that idea (although the rest of our works reveals a completely different shape for that trend)
Jim Cassidy wrote:Is there a cliff notes version of a) what the trend looks like b) a hypothesis about why the trend looks the way it does c) what are the implications for the overall understanding of the universe?
Users browsing this forum: Google Adsense [Bot] and 14 guests