Abundances in 4 Lacertae and ν Cephei
Abstract
Using Kurucz's ATLAS9 model atmospheres I performed LTE fine analyses of the supergiants 4 Lac and ν Cep. The spectra were obtained at 1.22-m telescope of the Dominion Astrophysical Observatory (DAO) by Saul J. Adelman. The atmospheric parameters were derived using the wings of Hβ and Hγ profiles for each star, and from Fe I/II, Fe II/III, and Si II/III equilibria for 4 Lac, and from Fe I/II and Cr I/II equilibria for ν Cep. A microturbulence of 2.7 km s-1 for 4 Lac was found from Fe II lines while a mean value of 5.2 km s-1 for ν Cep from Cr II, Ti II and Fe II lines. The rotational and macroturbulent velocities are, respectively, 14±2km s-1 and 15± 2 km s-1 for 4 Lac, and 26 ± 2km s-1 and 12 ± 2km s-1 for ν Cep. Their He, CNO and light element abundances are solar or overabundant while their iron peak and heavy element abundances are solar or underabundant. The derived results show that 4 Lac has nuclearly processed matter in its photosphere while ν Cep does not.
- Publication:
-
The A-Star Puzzle
- Pub Date:
- December 2004
- DOI:
- 10.1017/S1743921305009919
- Bibcode:
- 2004IAUS..224..873Y
- Keywords:
-
- Stars; abundances; stars: evolution; stars: individual; (4 Lac;
- ν Cep).