2. |
- Tautvaisiene, Grazina, et al.
(författare)
-
Stellar abundance anomalies: open cluster NGC 7789
- 2004
-
Ingår i: Stars as Suns: Activity, Evolution and Planets. - 158381163X ; , s. 985-989
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- High-resolution spectra of six giants and three core-helium-burning "clump" stars in the open cluster NGC 7789 have been obtained on the Nordic Optical Telescope to investigate abundances of up to 19 chemical elements and to compare the elemental abundances in differently evolved stars. The overall metallicity of the cluster stars was found to be close to solar ([Fe/H]=-0.04 +- 0.05). Compared with the Sun, mean abundances in the investigated giants and clump stars suggest that carbon is underabundant by approximately the same value of 0.2 dex, the 12C/13C ratios lie in the range from 11 to 7. However, the nitrogen overabundance is larger in the clump stars. The mean C/N ratios are lowered to the values of 1.3 +- 0.2 in the clump stars and to the values of 1.9 +- 0.5 in the giants. Among other chemical elements an overabundance of sodium is noticeable and for some other alpha-elements may be suspected. Abundances of heavy chemical elements in all nine stars were found to be close to solar.
|
|