Study of the abundances of heavy elements in F-G type stars. I. Differential analysis of two metal deficient stars: HR 646 and HR 860.
Abstract
Summary. The high information-gathering power of the electronic camera has been used to observe (with reciprocal dispersion of 2 A/mm) the faint lines produced by heavy elements. This enables to determine abundances with precision, since these lines are independent of microturbulence and should be little (if at all) affected by NON-LTE effects. The spectra are analysed differentially (relative to the standard star And), and with special effort to obtain the best signal to noise ratio and the best precision. Model atmospheres are derived from the blanketed models of Peytreman. The two first stars analysed show a moderate iron deficiency (about -0.30 in logarithm) relative to 1) And, and no extra deficiency of heavy elements. Moreover the analysis confirms that calcium is less deficient than iron and does not contradict that Ti is less deficient and Mn more deficient than iron. Key words: stars - chemical composition - curve of growth - stellar atmospheres - model analysis
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 1973
- Bibcode:
- 1973A&A....23...63S