A Detailed Analysis of the Spectrum of Epsilon Virginis.
Abstract
Lines in the spectral range X 4500-6700 A have been identified on tracings of the spectrum of E Virginis (G8 III). Three plates had a dispersion of 1 A/mm and five plates a dispersion of 2 8 A/mm. The equivalent widths of 1400 lines have been measured From the width of weak, unblended lines either a macroturbulence 3 6 + 1 km/sec, or a rotation, V sin i = 4 8 * 1 3 km/sec, can be derived The profile of the lines are not known with sufficient accuracy to favor one of these two extreme interpretations microturbulence of from 2 to 3 km/sec is derived from the curves of growth; there is a tendency to obtain a higher value for ionized lines than for neutral lines A detailed analysis of the atmosphere has been performed, leading to the values: T,j = 49400 K * 1500; log g = 2 7 * 0 2; and log A = log A0 + 0 2 (probable errors) There is a good agreement between the spectroscopic gravity and the value obtained from reasonable values of the mass and radius of the star The chemical composition of the atmosphere agrees with the solar composition within the probable error, except perhaps for Na No systematic enrichment in heavy-element abundance can be detected between the birth of the sun and that of E Virginis, about 10' years ago Higher accuracy is needed, both in equivalent width measurements and in the physical basis of the theory, to reveal any difference that might be less than a factor of 2
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 1963
- DOI:
- 10.1086/147521
- Bibcode:
- 1963ApJ...137..431C