Photometric investigations of several early-type variable stars using the stereo satellite

• Main Author: Ozuyar, Dogus
• Published: University of Birmingham 2015
• Subjects: 500; QB Astronomy
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.649341

We present results from high-precision photometric monitoring of several bright early-type stars. The data cover five years and are collected by the STEREO satellite. Stellar types covered are a sample of CP, δ Scuti, and Be-stars. We describe STEREO data and data pipeline developed to produce final light curves. We studied long-term variations in the rotational periods of 14 CP stars. With our pipeline, we were able to accurately determine their periods, and hence we investigated any period changes. The second study concerned Be-stars and looked at the connection between disk structures and non-radial pulsations. STEREO photometric data were supported by spectroscopic information on the Hα line. As a result, we found that, in some cases, variations in emission line properties were connected with changes in pulsation characteristics, and we discussed the consequences of this situation. In the final study, which involved a sample of δ Scuti stars, STEREO data were used to investigate the stars' pulsational properties and to look for any possible changes in their pulsations. Pulsation constants and modes of the main frequencies were identified, and regular spacings in frequencies were examined. Several cases in which pulsational characteristics changed were also determined, and their consequences were interpreted.