Under-Developed and Under-Utilized Eclipsing Binary Model Capabilities

Abstract

Existing but largely unused binary star model capabilities are examined. An easily implemented scheme is parameterization of starspot growth and decay that can stimulate work on outer convection zones and their dynamos. Improved precision in spot computation now enhances analysis of very precise data. An existing computational model for blended spectral line profiles is accurate for binary system effects but needs to include damping, thermal Doppler, and other intrinsic broadening effects. Binary star ephemerides had been found exclusively from eclipse timings until recently, but now come also from whole light and radial velocity curves. A logical further development will be to expand these whole curve solutions to include eclipse timings. An attenuation model for circumstellar clouds, with several absorption and scattering mechanisms, has been applied only once, perhaps because the model clouds have fixed locations. However the clouds could be made to move dynamically and be combined into moving streams and disks. An area of potential interest is polarization curve analysis, where incentive for modeling could follow from publication of observed polarization curves. Other recent advances include direct single step solutions for temperatures of both stars of an eclipsing binary and third body kinematics from combined light and velocity curves.Keywords: binaries, starspots, line profiles, ephemerides, circumstellar attenuation, polarization INTERACTION OF UNDER-DEVELOPMENT AND UNDER-UTILIZATIONA binary star story of some years hence might begin: "once upon a time there was a model feature that needed further work (UD for under-developed), and another that could have been applied but was not (UU for under-utilized). UD was not dressed for the science scene and UU was all dressed up with no place to go." We have experienced both situations in the early growing pains of high definition television and 3D TV, where few promoters were covering production costs for lack of in-home receivers (UD) and few persons bought receivers for lack of on-air productions (UU)-an iterative loop with very slow convergence at startup. So development and utilization can interact, as in the modeling and analysis capabilities now to be discussed. GROWTH AND DECAY OF MAGNETIC STARSPOTS AND SPOT GROUPSAn observational pursuit in need of analytic progress is growth and decay (briefly aging) of magnetic starspots for tests of theoretical work on outer convection zones and their dynamos. A realistic aim is to establish the statistics of spot (and spot group) area versus time over ranges of star mass, composition, envelope rotation, and age, without attempts to assess configurational details. Many parameters compete for attention, so spot temperature variation can be disregarded to reduce the parameter count, given that magnetic spots are nearly black in the first approximation.This is an open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http:// creativecommons.org/licenses/by-nc/3.0/) w...

Frequent Flare Events on the Short-period M-type Eclipsing Binary BX Tri

“…In order to find out the proper photometric solution, the light curves with and without flare phenomenon are calculated, respectively. Here, our four-color light curves were simultaneously analyzed by using the Wilson -Devinney (WD) program (Wilson & Devinney 1971;Wilson 1979Wilson , 1990Wilson , 1994Wilson , 2012Wilson & Van Hamme 2003). During the process, we assumed the effective temperature to be T 1 =3735 K for the primary component, which was determined from the color index and taking into account that the temperature of the primary component T 1 is higher than the mean temperature of the binary (Dimitrov & Kjurkchieva, 2010).…”

Phenomenological Modeling of Newly Discovered Eclipsing Binary 2MASS J18024395 + 4003309 = VSX J180243.9+400331

“…Although the errors of the phenomenological parameters are not very large (up to few percent), there may be systematic errors up to a dozen percent due to the simplicity of the model. These estimates may be used as preliminary values for further modeling using extended physical models based on the Wilson & Devinney (1971) code and it's extensions (Wilson 1979(Wilson , 1994(Wilson , 2012(Wilson , 2014Zola et al 1997Zola et al , 2010Bradstreet 2005;Kallrath et al, 2009;Linnel 2012;Reed 2012;Rucinski 2010;Prsa et al 2012). Such study of eclipsing binaries with the CBNU observations are reported by Jeong & Kim (2013); Kim & Jeong(2012); Jeong & Kim (2011) and Kim et al (2010a).…”

The M Dwarf Eclipsing Binary Cu Cancri

“…Our analyses utilized the W-D binary system computer model (Wilson & Devinney 1971;Wilson 1979Wilson , 1990Wilson , 2007Wilson , 2008Wilson & Van Hamme 2009Wilson 2012a) and its Differential Corrections (hereafter DC) program. One might expect CU Cnc to be an easy example for light-curve solutions, judging from its well-detached morphology, circular orbit, and lack of major complications.…”