The main PHOEBE window is divided in 9 tabs - screen pages with selected content that fits into a specific category (Fig. 3). Data tab contains the information on experimental data, which is supplied by the user. System-related tab holds all parameters that characterize the binary system as a whole - such are the epoch parameters, semi-major axis, mass ratio and so on. Component-related tab, in contrast, contains curve-independent parameters that are characteristic of each star individually, such as the effective temperature and gravity potentials. Orbit tab contains parameters that describe the orbit, like orbital ellipticity. There is planned support for Roche geometry graphs. Next tab, Luminosities, contains curve-dependent parameters: they have different values for different filters. Typical parameters that fit into this category are flux levelers,
light and weighting functions. Limb darkening and Surface tabs contain parameters that contribute in perturbative orders of corrections to curves. Finally, the Fitting tab contains functions and parameters that define and support minimization algorithms. Utilities tab holds functions that are not directly connected to PHOEBE and prototypes for functions to be implemented into PHOEBE shortly.
Beside the main window there are three other types of PHOEBE windows. Calculation windows help the user to quickly estimate the values of some specific parameters, such as limb darkening coefficients and gravity potentials. Plotting windows are meant for quick and simple eye inspections of both experimental and synthetic light and radial velocity curves. A Fitting window guides the user through the minimization process and iterative solution convergence. Finally, a Scripter window enables the user to write and execute powerful PHOEBE scripts.
All windows may be open at the same time because of the modular design of PHOEBE. It is up to you to decide the layout that suits you best, PHOEBE poses no limitations in this respect. You may not, however, have more copies of the same window, since the contents of one window might not be the same as the contents of another instance of the same window and this might lead to ambiguity problems.
The very top of the PHOEBE window is occupied by a drop-down menu. Here you will find other actions PHOEBE can perform.
On the bottom of the main PHOEBE window there's a status bar (labelled Last Event), where PHOEBE notifies you of all events when they are initiated. There is planned support for history browsing and undoing unwanted changes, which will be closely related to events in the status bar.
Finally, the lowermost part of the main PHOEBE window is occupied with a button box. The buttons in this box let you quickly perform some specific operations. Open and Save buttons let you manipulate PHOEBE keyword files - files containing all the information about a certain star and are usually identified by the suffix .phoebe. The Defaults button restores all parameter values and entries to a state they were at startup. LC Plot and RV Plot buttons open the plotting windows, Fitting takes you to the fitting window, Help button will eventually bring up the online help screen, but this is not implemented yet. Finally, the Exit button closes all PHOEBE windows and exits the program.
