Ultraviolet photometry with the Astronomical Netherlands Satellite ANS: the helium-spectrum variables CU Vir and SX Ari.
Abstract
Summary. The ANS ultraviolet photometric experiment observed the helium-spectrum variables CU Vir and SX Ari. A single observation of SX Ari was obtained showing ultraviolet colors similar to those for a late B star. For CU Vir 18 high quality observations resulted in light curves showing a possible "null region" near 2000 A where the adjacent continua vary in opposition with respect to each other. An oblique-rotator model of the silicon distribution determined from spectral variations is used in a new technique to predict light curves induced by silicon backwarming. There is sufficent qualitative agreement to state that silicon is a major source for the photometric variations of CU Vir, although there are other secondary sources. Key words: Ap stars - silicon opacity - flux redistribution - backwarming - helium-spectrum variables
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 1978
- Bibcode:
- 1978A&A....63..335M
- Keywords:
-
- A Stars;
- Astronomical Netherlands Satellite;
- Stellar Spectrophotometry;
- Ultraviolet Astronomy;
- Variable Stars;
- Helium;
- Light Curve;
- Photosphere;
- Silicon;
- Astronomy;
- Peculiar A Stars:Oblique Rotators;
- Spectrum Variables:UV Photometry