A spectroscopic analysis of the eclipsing Nova-like EC21178-54

• Main Author: Khangale, Zwidofhelangani Ndamulelo
• Other Authors: Woudt, Patrick Alan
• Format: Dissertation
• Language: English
• Published: University of Cape Town 2014
• Online Access: http://hdl.handle.net/11427/9185

Includes bibliographical references. === EC21178-54 is a 13.7 magnitude eclipsing nova-like (NL) cataclysmic variable (CV) discovered in the Edinburgh-Cape survey of blue objects. It has an orbital period of 3.708 hours. High-speed photometric analysis of its light curve reveal that this system is a rich source of quasi-periodic oscillations (QPOs), dwarf nova oscillations (DNOs) and the other type of periodic oscillations called longer period dwarf nova oscillations (lpDNOs). Its light curve shows a deep symmetrical V-shaped primary eclipse, and its spectra show strong broad double-peaked emission. In this project we present phase-resolved spectroscopy of the eclipsing nova-like CV EC21178-54. The average spectrum of EC21178-54 shows broad double-peaked emission lines from HeII 4686Å, and the Balmer series. HeII 4686Å dominates the Balmer lines; and in the Balmer lines the blueshifted component is the stronger of the two. The high-excitation feature, CIII/NIII at 4640-4650 Å, is also present and appear broad in emission. A number of other lines, mostly HeI, are clearly present in absorption and/or emission.