A Search for Long and Short Term Variations in the Spectrum of a Centauri.
Abstract
Equivalent width and central depth measurements of the ultraviolet absorption lines from the spectrum of the He1 variable star a Cen are presented. The measurements are from short wavelength, and long wavelength, high resolution spectrographs taken with the International Ultraviolet Explorer (IUE) satellite. Central depth measurements were of lines of Cr3, Mn3, V3, C3, Si2, and S2 seen in the region between 1245 and 1255 A. Equivalent widths are of the three He1 2(3)s-n(3)P(0) transitions found at 2945, 2829 and 2764 A. The period for cyclic intensity variations in He1 is determined using a four parameter, least squares fit to a sinusoid. The IUE observations alone match both a period + or - of 8.8163 + or - 0.0003 days and a previously unreported period of 9.2532 + or - 0.0003 days with equal minima for the least squares fit. The phase of C3 maximum relative to He1 maximum is found to be 0.53 cycles for the IUE observations.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1980
- Bibcode:
- 1980PhDT.........1F
- Keywords:
-
- Physics: Astronomy and Astrophysics;
- Periodic Variations;
- Stellar Spectra;
- Ultraviolet Absorption;
- Variable Stars;
- Iue;
- Least Squares Method;
- Satellite Observation;
- Sine Waves;
- Spectrographs;
- Astronomy