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.

Abstract.We have found photometric indications that Interacting Eclipsing Binaries of early to mid F spectral type (and possibly A) have strong magnetic activity which would arise from convective atmospheres. Light curve solutions and periodicity studies revealing spots, magnetic breaking and magnetic cycles are presented in XZ CMi, V965 Cyg and V963 Cyg.Keywords. Stars: activity, stars: binaries: eclipsing, convection V963 CygniOur analysis of UBVR c I c observations of V963 Cygni taken 19-25 July 2004 indicates that it is a detached F6.5 ± 1 binary. The light curves show strong distortions in the out-of-eclipse portions, which we assumed are due to several large spot regions. If this assumption is correct, V963 Cyg has strong magnetic activity. In addition, the outof-eclipse portions of the light curves have somewhat different shapes in each effective wavelength. Particularly, the R curve is very different from the B curve in the shoulder of the secondary eclipse.As with the other systems included with this paper, we premodeled the light curves with Binary Maker 3.0 (Bradstreet 2002) and then used the resulting parameters as starting values for a simultaneous light curve solution with the updated 2004 Wilson Code (Wilson & Devinney 1971, Wilson 1990, 1994. This code includes full stellar atmospheres based on Kurucz atmospheres, rather than those of a black body, and a detailed reflection treatment along with 2-D limb darkening coefficients. In addition to spot modeling for this binary, we tried adjusting the F parameter (nonsynchronous rotation) and third-light. Both of these gave negligible values. Our best solution indicates that the binary is a detached system with a mass ratio = 0.85 ± 0.01. The component temperature difference was only about 280 K. This solution used 4 spots: 1 cool spot on component 1, and 3 hotspots on the second component. We note here that the eclipses are partial, so our model is preliminary in nature, but a mass ratio near one is strongly suggested. Radial velocity curves are needed for a complete solution.

Frege claims that sentences of the form 'A' are equivalent to sentences of the form 'it is true that A' (The Equivalence Thesis). Frege also says that there are fictional names that fail to refer, and that sentences featuring fictional names fail to refer as a result. The thoughts such sentences express, Frege says, are also fictional, and neither true nor false. Michael Dummett argues that these claims are inconsistent. But his argument requires clarification, since there are two ways The Equivalence Thesis has been formulated, according as the thesis equates the senses or the referents of the relevant sentences. I have two aims in this paper. The first is to demonstrate that a sameness of sense thesis is inconsistent with Frege's other theses. The second is to argue that a sameness of reference thesis is consistent with them. Thus, all else being equal, Frege ought to endorse a sameness of reference, rather than a sameness of sense thesis.