The blue stragglers of M 67.
Abstract
Spectroscopic observations of 11 blue stragglers of the open cluster M67 were made at medium resolution at the European Southern Observatory to derive constraints on their nature and origin. A detailed abundance analysis of two of them, F153 and F185, show that both of them have very similar abundance patterns, except for calcium and scandium. The following features were found to be common to both stars: the abundances of most elements, including iron, are solar within a factor of 2, and they are consistent with the main-sequences abundances in M67, when the latter have been determined; zinc, strontium, yttrium, zirconium, and barium are strongly overabundant; and the abundance of nitrogen is close to solar, while carbon and oxygen are underabundant by about -0.7 dex. Consideration of the equivalent width of the O I triple 7773 A revealed that oxygen has a solar abundance or is underabundant by at most -1 dex in the 11 studied blue stragglers.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- May 1991
- Bibcode:
- 1991A&A...245..467M
- Keywords:
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- Blue Stars;
- Open Clusters;
- Stellar Evolution;
- Hertzsprung-Russell Diagram;
- Stellar Magnetic Fields;
- Stellar Rotation;
- Astrophysics