Non-resonance lines of neutral calcium in the spectra of the alpha Centauri binary system.
Abstract
Selected regions containing calcium lines of moderately high excitation (2.5 eV) in the spectra of α Cen A and α Cen B have been recorded at a dispersion of 1.5 Å mm-1 and with signal/noise ≡100 using a silicon diode array (Reticon). Both stars are found to be metal-rich by 0.2 dex compared to the Sun: α Cen A has Teff = 5820±50K and log g = 4.4±.1; α Cen B has Teff = 5280±100K and log g = 4.65±.15. The analysis of calcium lines reveals that the microturbulence in α Cen A is identical to that in the solar atmosphere and larger than the microturbulence in α Cen B. Line profiles in α Cen B are significantly narrower than those in α Cen A and it seems probable that the difference in microturbulence is accompanied by a difference in macroturbulence.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- September 1986
- Bibcode:
- 1986A&A...165..126S
- Keywords:
-
- Binary Stars;
- Calcium;
- Centaurus Constellation;
- Emission Spectra;
- Stellar Composition;
- Stellar Spectra;
- Abundance;
- Magnetohydrodynamic Turbulence;
- Metallicity;
- Stellar Temperature;
- Astrophysics