Non-resonance lines of neutral calcium in the spectra of Arcturus and beta Virginis.
Abstract
Selected regions containing calcium lines of moderately high excitation (2.5-3.0 eV) in the spectra of Arcturus (K2III, m/v/ =0.0) and Beta Virginis (F8V, m/v/ =3.6) have been recorded at a dispersion of 1 A/mm and with signal/noise of approximately 100 using a silicon diode array. A conventional analysis, based on an LTE model atmosphere and using all relatively unblended lines for which precise oscillator strengths are now available, leads to extremely consistent values for calcium abundance and microturbulence. The microturbulence is shown to have a value of about 1.5 km/s in both stars. There is marginal evidence for a departure from LTE in one multiplet in the Arcturus spectrum. The dependence of the derived abundance on model atmosphere, effective temperature, and surface gravity is investigated.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- January 1983
- Bibcode:
- 1983A&A...117..177S
- Keywords:
-
- Abundance;
- Atmospheric Turbulence;
- Atomic Spectra;
- Calcium;
- Stellar Atmospheres;
- Stellar Spectra;
- Atmospheric Models;
- Electron Oscillations;
- Neutral Atoms;
- Silicon Radiation Detectors;
- Spectral Line Width;
- Subgiant Stars;
- Astrophysics