Extreme-mass-ratio solar-type binaries and their implications for cluster environs

Abstract

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.

UBVRcIcANALYSIS OF THE RECENTLY DISCOVERED TOTALLY ECLIPSING EXTREME MASS RATIO BINARY V1853 ORIONIS, AND A STATISTICAL LOOK AT 25 OTHER EXTREME MASS RATIO SOLAR-TYPE CONTACT BINARIES

“…If there is a third light, it is much fainter than the components of the system. Even in this case, a future extended period study may detect its presence (Samec et al 2010).…”

“…Next, the mean values from the fits generated a set of starting values for the Wilson code (Wilson & Devinney 1971;Wilson 1990Wilson , 1994Van Hamme & Wilson 1998). From these, the differential corrections routine was Due to the common occurrence of third bodies in WUMa systems (Pribulla & Rucinski 2006;Tokovinin 2006;Samec et al 2010), a third light was included as an adjustable parameter for a brief time in the iterations. The results showed the values of the third light were negligible and less than the uncertainties.…”

“…EMRBs should all have near-zero ΔT's, but that is not the case (Figure 11). This initial set of these results was given in an IAU 2009 poster (Samec et al 2010), and is now published here. More results will certainly follow.…”

“…During the past decade, the number of known shallow amplitude, extreme mass ratio solar-type contact binaries (EMRBs) has steadily been increasing (Samec et al 2010). More than 25 are presently known.…”