The Eclipsing Binary U Sagittae.
Abstract
A series of 148 spectrograms of U Sagittae have been obtained with the McDonald and Mount Wilson spectrographs. The H lines give systematically different velocities from the other star lines at certain phases in the cycle. The orbital elements and radial-velocity-curve have been determined from all the star lines present except the H lines and the Ca Ir K line. The H velocities are controlled primarily by measurements of the cores present within the H lines, which are usually displaced to the red or violet of the center of the broad H wings. Near phase 0.88P the H asymmetries change from red-displaced cores to violet-displaced cores without any apparent change in the displacement of the H velocities from above the velocity-curve. From phase 0.88F to phase 0.93P neither the H cores nor the center of the H wings gives velocities consistent with the other star lines. The discordant H velocities can be only partially explained on the basis of absorption in gaseous streams. Very rapid changes in the H-line velocities are present at phases 0.73, 0.125, and 0.20P.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- November 1951
- DOI:
- 10.1086/145495
- Bibcode:
- 1951ApJ...114..513M