The Future as Seen in


In addition to the improvements described above that are only partially implemented at present, a number of additional improvements are in the process of being implemented and still others can be foreseen. These include the following:

Direct distance estimation as described in Sect. 5.1.4 and Wilson (2008) will be available in the 2009 version of the WD program. This is based on absolute calibrated light curves which permits the determination of the temperatures of both components and the comparison of computed absolute, distance-dependent flux with the observed flux. This feature also allows the fitting of the interstellar extinction attenuation, Ax, i.e., for specific passbands at effective wavelength A.

Inverse distance estimation exploits distances obtained, for example, by the HIPPARCOS and GAIA missions to constrain the solution and to reduce correlations among parameters.

Analysis of an eclipsing binary component with pulsations: Future editions of the WD program may include the physics of pulsating variable stars. Progress toward such a goal is in preparation by Wilson (2009).

Discontinuous period changes (Wilson 2005) also discusses possible implementation of discontinuous period changes.

Continuum and spectral line polarization modeling: This feature is available in a new version of WD under development by Wilson.

Addition of other adjustable parameters: There is provision in the 2007 version of WD to include more adjusted parameters. One of the most useful of these could be di/dt. It has been found in several eclipsing systems that the inclination varies with time, due to the presence of a third body in the dynamical system of the binary. This situation proved to be the case with the system SS Lacertae, for example. A group of parameters that could be useful are those that stipulate the shape of spotted regions on the stars. In his program LIGHT2 described in Sect. 6.3.3, Graham Hill incorporated elliptical spots. Spot groups may be represented better by such a shape than a circular set of spots. The major axis size could replace the current spot radius, but the ellipticity and major axis orientation would have to be adjustable also, or at least they would need to be specifiable.

Incorporation of stellar tomography into WD codes. The discussion of the SHELLSPEC software in Sect. 2.5 indicated how powerful a tool this can be in the case where specific spectral features can be associated with specific regions in a binary star system. It would be very useful to be able to incorporate such a tool into general light curve analysis software.

Facilitation of Passband additions. In the wd9 8k93 program and the WD9 8 package, instructions were provided to create new "flux files," so that additional passband data could be modeled. In the current WDx2 0 07 program, however, the passbands are "hard-wired" so that alterations to the program are required to add new passbands. This cannot be done frequently, and pressure to do so would create a nightmare for Robert Wilson and Walter Van Hamme who have already spent a great deal of time and effort to make the program as self-contained as possible with regard to stellar atmosphere application. Therefore, it would be useful to allow additional passbands to be added by the user.


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