The effect of line blocking on the light curves of the Ap star HR 5355 (HD 125248).
Abstract
Line-blocking coefficients were measured from coude spectrograms covering the blue and green parts of the spectra, throughout the 9d3 cycle of HR 5355. The coefficient for the V band of the uvby photometry is found to vary through a range of 0" 06 of the continuum in a double wave, with maxima corresponding to the maxima of both the Eu ii and the Cr spectrum variation, which occur in antiphase. This line blocking cannot account for the strong single-wave light variation in the V band, which has a minimum at rare-earth maximum, but may be responsible, by redistribution of flux, for the double-wave character of the b- and y-band light variations. There is little variation of line blocking in the b and y bands. Line blocking varies significantly with wavelength and with phase in the vicinity of 5200 A, and is partially responsible for the minimum in the apparent continuum found by photometric observers. It does not appear to be possible to interpret the basic light variations of HR 5355 by the mechanisms recently proposed for this and other Ap stars. Key words: peculiar A stars - line blocking - spectrum variation - light variation
- Publication:
-
Publications of the Astronomical Society of the Pacific
- Pub Date:
- April 1975
- DOI:
- Bibcode:
- 1975PASP...87..221P
- Keywords:
-
- A Stars;
- Light Curve;
- Line Spectra;
- Stellar Spectra;
- Chromium;
- Europium;
- Spectrum Analysis;
- Stellar Magnetic Fields;
- Stellar Spectrophotometry;
- Ultraviolet Spectra;
- Astronomy