The Evolution of Oxygen and Magnesium in the Bulge and Disk of the Milky Way

Astronomy and Astrophysics – Astrophysics

Scientific paper

Rate now

  [ 0.00 ] – not rated yet Voters 0   Comments 0

Details

22 pages including 5 figures. Submitted to the Astronomical Journal

Scientific paper

10.1088/0004-6256/136/1/367

We show that the Galactic bulge and disk share a similar, strong, decline in [O/Mg] ratio with [Mg/H]. The similarity of the [O/Mg] trend in these two, markedly different, populations suggests a metallicity-dependent modulation of the stellar yields from massive stars, by mass loss from winds, and related to the Wolf-Rayet phenomenon, as proposed by McWilliam & Rich (2004). We have modified existing models for the chemical evolution of the Galactic bulge and the solar neighborhood with the inclusion of metallicity-dependent oxygen yields from theoretical predictions for massive stars that include mass loss by stellar winds. Our results significantly improve the agreement between predicted and observed [O/Mg] ratios in the bulge and disk above solar metallicity; however, a small zero-point normalization problem remains to be resolved. The zero-point shift indicates that either the semi-empirical yields of Francois et al. (2004) need adjustment, or that the bulge IMF is not quite as flat as found by Ballero et al. (2007); the former explanation is preferred. Our result removes a previous inconsistency between the interpretation of [O/Fe] and [Mg/Fe] ratios in the bulge, and confirms the conclusion that the bulge formed more rapidly than the disk, based on the over-abundances of elements produced by massive stars. We also provide an explanation for the long-standing difference between [Mg/Fe] and [O/Fe] trends among disk stars more metal-rich than the sun.

No associations

LandOfFree

Say what you really think

Search LandOfFree.com for scientists and scientific papers. Rate them and share your experience with other people.

Rating

The Evolution of Oxygen and Magnesium in the Bulge and Disk of the Milky Way 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 The Evolution of Oxygen and Magnesium in the Bulge and Disk of the Milky Way, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Evolution of Oxygen and Magnesium in the Bulge and Disk of the Milky Way will most certainly appreciate the feedback.

Rate now

     

Profile ID: LFWR-SCP-O-205287

  Search
All data on this website is collected from public sources. Our data reflects the most accurate information available at the time of publication.