Dissertation Information for Styliani KafkaNAME:
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SCHOOL: ADVISORS: COMMITTEE MEMBERS: MPACT Status: Incomplete - Not_Inspected Title: Exploring stellar activity on the secondary star of cataclysmic variables Abstract: The light curves of Cataclysmic Variables (CVs) exhibit a plethora of behaviors, from ephemeral changes (flickering) to large nova explosions; most are attributed to the accretion process. During the last couple of decades, it has been realized that activity (starspots) and activity cycles on the secondary star can be responsible for (quasi-periodic) modulations observed in long-term CV light curves, and may moderate, even halt accretion from the secondary star. The latter can lead to observed large drops in the system luminosity (VY Scl low states); the presence of low states in both magnetic and disk systems directs attention to the secondary star for their cause. Activity on the K-M dwarf mass-losing secondary is commonly invoked to explain sustained mass transfer caused by system angular momentum loss via a magnetized stellar wind, quasi-periodic changes in the mass transfer rate, the elusive CV period gap, and widely differing mass transfer rates among CVs at the same orbital period. On the other hand, there is a substantial lack of observational support for these scenarios, since conventional activity indicators (X-ray and Ha emission; flares) are usually mimicked by accretion. |
MPACT Scores for Styliani KafkaA = 0 Advisors and Advisees Graph |