The chemical compositions of the distant galactic openclusters Bochum 1 and NGC 1893.
Abstract
High resolution spectroscopy of main-sequence B-type stars in two galactic open clusters, with galactocentric distances greater than 13 kpc, have been obtained using the Isaac Newton Telescope. Two stars in Bochum 1 and six stars in NGC 1893 have been analyzed using LTE model atmosphere techniques to derive photospheric chemical compositions. Since these stars are at an early evolutionary stage, the photospheric abundances should reflect those of their progenitor interstellar material. There is no evidence for any systematic underabundances of metals for these two clusters, which is in contrast to the chemical composition found for the metal poor cluster Dolidze 25 at a similar galactocentric distance (Lennon et al., 1990). We conclude that the chemical composition may not be unique at distant galactocentric radii, R(g), as well as the variation of abundance with R(g) not being linear.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- March 1993
- Bibcode:
- 1993A&A...270..107R
- Keywords:
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- B Stars;
- Chemical Composition;
- Galactic Structure;
- Main Sequence Stars;
- Open Clusters;
- Astronomical Spectroscopy;
- Early Stars;
- Stellar Composition;
- Astrophysics