A Spectrophotometric Analysis of Two Metallic-Line Stars.
Abstract
Equivalent widths have been measured on Mount Wilson coude spectra of the two metallic4ine stars, 8 Comae and 15 Vulpeculae Line profiles of some Balmer lines and the K line of Ca ii have also been determined. The data are analyzed by curve-of-growth procedures, and the results indicate that the two stars resemble each other closely in their physical properties They show high turbulent velocities of 4.8 and 3.8 km/sec, as does another metallic-line star, r Ursae Majoris, implying that high atmospheric turbulence is definitely linked with metallicism. Opacity, ionization temperature, electron and gas pressure are also derived The effective gravity determined spectroscopically is about ten times smaller than the gravitational value. Abundances of chemical elements do not differ from those of the sun by more than a factor of 3, except in the cases of Sc, Ca, Na, Sr, and Zn. Equivalent widths of lines in r UMa, measured by Greenstein (1948), have been reanalyzed by use of the same line strengths (Bell 1950) as those used for 8 Com and 15 Vul A comparison of 8 Com and 15 Vul with r UMa shows that the first two exhibit similar, but less pronounced, abundance effects Lack of a model prevents a reliable determination of the hydrogen abundance Line strengths for more than five hundred lines are tabulated.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 1956
- DOI:
- 10.1086/146210
- Bibcode:
- 1956ApJ...124..134M