NOAO >   Observing Info >   Approved Programs >   2003B-0095

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Proposal Information for 2003B-0095


PI: Styliani Kafka, Indiana University, skafka@astro.indiana.edu
Address: Astronomy Department, Swain Hall West, Bloomington, IN 47405, US

CoI: Kent Honeycutt, Indiana Univestity

Title: Chromospheric Activity in M dwarfs and Changes in the Mass Transfer Rate

Abstract: Most types of compact binary systems have variable mass transfer rates (\dotM) on many time scales. These effects are often attributed to magnetic activity on the mass-losing secondary star. However, these theories have little or no direct observational evidence because the usual indicators for stellar activity are masked by emission from the accretion disk. We propose to acquire near-infrared spectra to test the hypothesis that \dotM is controlled by activity on the secondary star, using activity-sensitive ratios of the strengths of absorption features arising from the secondary star in cataclysmic variables (CVs). The outburst recurrence intervals of dwarf nova (DN) are determined by \dotM, permitting a test by comparing the activity level in DN having very different outburst intervals but similar orbital periods. We will also obtain spectra in the low state of VY Scl stars, whose low states have been attributed to stellar activity on the secondary star.


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