We present precision CCD light curves, a period study, photometrically derived standard magnitudes, and a fivecolor simultaneous Wilson code solution of the totally eclipsing, yet shallow amplitude (A v ∼ 0.4 mag) eclipsing, binary V1853 Orionis. It is determined to be an extreme mass ratio, q = 0.20, W-type W UMa overcontact binary. From our standard star observations, we find that the variable is a late-type F spectral-type dwarf, with a secondary component of about 0.24 solar masses (stellar type M5V). Its long eclipse duration (41 minutes) as compared to its period, 0.383 days, attests to the small relative size of the secondary. Furthermore, it has reached a Roche lobe fill-out of ∼50% of its outer critical lobe as it approaches its final stages of binary star evolution, that of a fast spinning single star. Finally, a summary of about 25 extreme mass ratio solar-type binaries is given.

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Abstract. During the past decade, the number known shallow-amplitude, yet totally eclipsing, extreme-mass-ratio binaries has increased from one (AW UMa, which is now in doubt) to about a dozen. Statistics are accumulating that will tell us the nature of these once rare systems. These individual interacting field binaries are believed to be the progenitors of FK Comae-type fast-rotating subgiants, which are similar to the cluster stars called 'variable blue stragglers.' We review our recent observations and new analyses of the individual systems, V409 Hya, GSC 1283 0053 Ori, GSC 2537 520 CVn, using the 2007 Wilson Code and summarize results from our previous observations (V802 Aql, V902 Sgr) and those from the literature (e.g., CK Boo, GR Vir, HV Aqr, UY UMa, EM Pis, CU Tau, TV Mus) to disclose a preliminary picture of the character of this interesting class of binary stars. Keywords. magnetic fields, binaries: eclipsing, blue stragglersThe full poster (in pdf format) is available at http://www.astro.iag.usp.br/~iaus266/Posters/pSamec.pdf. AcknowledgementsOur recent CCD observations were taken with the Lowell 0.81 m telescope through our association with NURO (the National Undergraduate Research Observatory) and the SARA (Southeastern Association for Research in Astronomy) 0.9 m telescope. We gratefully acknowledge travel support received through the small research grant program of the American Astronomical Society.

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Abstract. Solar-type variability is enhanced in short period close binaries with increased dynamo driven activity. This activity is studied in our analysis of recent light curves taken of the newly discovered eclipsing binaries GSC 2764 1417 (And), GSC 3355 0394 (Per) and GSC 2537 0775 (CVn).Keywords. binaries: close, stars: activity, spots, mass loss, winds, outflows; techniques: photometric Observations and AnalysesOur recent CCD observations of these variables were taken with the Lowell 0.81-m though our association with NURO (the National Undergraduate Research Observatory) and the SARA (Southeastern Association for Research in Astronomy) 0.9-m telescope. Times of minima were calculated, period studies were carried out and orbital behaviors were determined and used to phase present light curves. B,V,R,I light curves were hand premodeled with Binary Maker 3.0 (Bradstreet 2002). Average parameters were used as initial input values for a simultaneous 4 color synthetic light curve calculation with the